JP5488386B2 - Active energy ray-curable hot melt urethane resin composition, electronic device member using the same, and packing - Google Patents

Description

The present invention relates to an active energy ray-curable hot melt urethane resin composition, an electronic device member using the same, and a packing.
More specifically, the active energy beam has two characteristics, that is, a hot melt property that is rapidly solidified by cooling after coating, and a fast curing property by irradiation with active energy beams such as ultraviolet rays, electron beams, X-rays, infrared rays, and visible rays. A curable hot melt urethane resin composition that retains its shape, flexibility, mechanical strength, durability (especially hydrolysis resistance), and substrate adhesion (particularly metal adhesion) after application to the substrate. It is excellent in low outgassing property (including reworkability), and relates to a member for electronic equipment and packing using the same.

  Magnetic disk devices are becoming increasingly important for computers as large-capacity, high-speed and economical storage devices, and more recently, miniaturization is rapidly progressing.

  The magnetic disk drives used for these are fixed in a sealed structure with a hard disk drive packing (hereinafter abbreviated as “HDD packing”). By using the sealed structure, dust and contaminants enter and vibrate. Prevents malfunctions and breakdowns, high-density recording, compact structure, miniaturization, and high reliability.

  In addition, HDD packing has a packing function that ensures flexibility after application to the substrate, as well as flexibility, durability (especially hydrolysis resistance), and substrate adhesion (especially adhesion to metal). ), Excellent performance such as low outgassing is required.

  Conventionally, in order to prevent such dust and contaminants from entering and vibrating, as a method of providing a sealing material (ie, packing) between the housing of the magnetic disk drive and the housing, for example, a sponge cut into a band shape A porous material having elasticity such as cork or cork has been used.

  However, in such a method, a band-like sponge or cork is manually bonded around the area in contact with the lid of the housing with a thermosetting adhesive. In addition, at least two processes of applying an adhesive and bonding a sponge or the like are indispensable and extremely inefficient. Furthermore, since the housing has a structure formed of plastic, when a thermosetting adhesive is used as the adhesive, there is a problem that the housing is deformed by heat.

  Therefore, in recent years, in the assembly and manufacturing of magnetic disk drives and their components, UV curable resin compositions are used for fixing and joining each component in order to meet the demands for reducing work time and cost reduction by avoiding the heating process. Active energy ray-curable resin compositions such as products are used.

  As an example of this, an ultraviolet curable resin composition having elasticity is used as a sealing material provided between the magnetic disk drive housing and the lid of the housing, and the periphery of the surface of the magnetic disk drive housing that covers the lid. There is known a method of providing a sealing material on a housing for a magnetic disk drive that coats the ultraviolet curable resin composition using a nozzle at a location, and then cures the coating by irradiating ultraviolet rays (for example, Patent Documents). 1).

  In this method, for example, an ultraviolet curable resin using an unsaturated acrylic resin, a polyester acrylate, a urethane acrylate, an epoxy acrylate, a polyene-polythiol addition polymerization resin, a cationic polymerization resin, an unsaturated polyester resin, or the like as an ultraviolet curable resin. After applying the resin composition with a nozzle, the resulting coating is cured by irradiating with ultraviolet rays to form an elastic sealing material, which can prevent dust and contaminants from entering and vibrating. And since it can be used as a sealing material quickly and is applied by a nozzle, it can be arbitrarily adjusted to a desired thickness and width.

  However, in the ultraviolet curable resin composition used in Patent Document 1, since there is a large amount of outgas generation due to residual monomers after irradiation with ultraviolet rays, troubles such as malfunctions and failures occur during signal recording and reading. There was a problem that it was likely to occur.

  Therefore, in order to reduce the residual monomer that is the main causative substance of such outgas generation, normally, a long-time heat treatment under high temperature conditions has been performed in advance when obtaining a resin composition. There is only a slight effect in reducing the outgas, which is not an effective means, and has a problem that it is extremely inferior in productivity because it requires labor and processing time.

  Also, at least one bifunctional (meth) acrylate represented by a specific general formula, at least one monofunctional (meth) acrylate represented by a specific general formula, a styrene-isobutylene block copolymer, a photopolymerization initiator, And the manufacturing method of the photocurable sealing agent which mixes silica powder as an essential component is known (for example, refer patent document 2).

  Since the photocurable sealant obtained by such a manufacturing method has good moisture permeation resistance and elasticity, it includes electronic circuit elements such as hard disks and seals of electronic component housings in which electronic components are contained, and others. It is said that it is useful as a moisture-permeable sealant in a member that requires a moisture-permeable property.

  However, the photocurable sealing agent described in Patent Document 2 also has a large amount of outgas generation due to residual monomers after being irradiated with ultraviolet rays and cured, as in Patent Document 1, so when recording or reading signals. There was a problem that troubles such as malfunction and failure were likely to occur.

  Further, in the ultraviolet curable composition used for assembling each part of the hard disk device, the curable component of the ultraviolet curable composition uses either an organic zinc or an amine compound as an addition reaction catalyst between an isocyanate group and active hydrogen. It is a urethane (meth) acrylate obtained by addition-reacting the hydroxyl group of the hydroxyalkyl (meth) acrylate and the isocyanate group of the isocyanate oligomer to the isocyanate oligomer prepared as described above using either an organic zinc or an amine compound as a catalyst. An ultraviolet curable composition for assembling a hard disk device is known (see, for example, Patent Document 3).

  Such an ultraviolet curable composition does not contain a tin compound and does not contain an outgas component. Therefore, it includes hard disk device components (such as a housing case packing of a hard disk device, a cap seal of a spindle motor, a magnetic head fixing, a substrate and a connector) It can be used for fixing or joining.

  However, the ultraviolet curable composition obtained in Patent Document 3 (1) requires a curing process by irradiation with active energy rays to ensure shape retention, and (2) a large amount of low molecular weight prepolymer and residual MDI. In other words, the crosslink density is too high to be hardened, and (3) there is a large amount of residual monomer after curing, and disk reading failure due to outgassing tends to occur.

  In addition, as the resin used in the active energy ray-curable resin composition, for example, polymer oligomer acrylate compounds have been studied, but satisfactory results have been obtained with respect to the reduction of the outgas generation amount. It wasn't.

  In addition to active energy ray-curable resins, various materials such as rubber-based elastomers and foamed polyurethane resins with adhesives have been studied as resins used in HDD packing. Due to the large amount of outgas generated, malfunctions and failures occurred frequently during signal recording and reading, and the solution could not be solved. As a countermeasure, for example, degassing was previously performed by heat treatment under high temperature conditions. However, such a method was extremely inferior in productivity, and the outgas reduction effect was not sufficient.

  Furthermore, recently, with the increase in storage capacity and accuracy of hard disks and the remarkable increase in information processing speed, extremely small amounts of outgas components, which were not previously considered as the cause of malfunctions and failures, have appeared on the surface of magnetic disks. There has been a concern that even if it is attached to the hard disk drive, a device such as a hard disk drive having a large storage capacity may cause a serious failure.

  Thus, during assembly or manufacturing, if a very small amount of dust or contaminants enter the hard disk drive and adhere to the surface of the magnetic disk, it can cause frequent malfunctions and failures during signal recording and reading. For this reason, there is a strong demand for the use of a resin composition with a low outgas generation amount in the active energy ray-curable resin composition itself such as an ultraviolet curable resin composition used for assembling a hard disk drive. It was.

  By the way, in a hard disk drive, since a built-in disk rotates at high speed, parts are joined and fixed with a rubber-like elastic body capable of absorbing vibration generated during the high-speed rotation motion. Therefore, as the active energy ray-curable resin used for bonding and fixing, a resin mainly composed of a urethane acrylate compound that forms a cured product having a relatively high flexibility has been generally used.

  However, in the case of commonly used urethane (meth) acrylate compounds, organotin compounds are included as catalysts, so outgas components due to residual monomers after curing are likely to occur, and these outgas components adhere to the disk surface. However, it has tended to induce malfunctions and failures when recording and reading signals, and has been a problem in the past.

  On the other hand, adhesives that use organic solvents are harmful to workers, fire hazards, environmental pollution, drying speed delays, solvent consumption, etc.・ Reactive hot melt urethane adhesives are being actively investigated as environmentally friendly adhesives. Such reactive hot-melt urethane adhesives are used in a wide range of applications such as coating agents, as well as adhesives for building materials and fibers, as high-value-added products that replace conventional solvent-based resins and water-based resins. It is being

  The reactive hot melt urethane adhesive is solid at room temperature and melts to form a liquid or viscous property when heat is applied. It has both “moisture curability”, which is a property that provides adhesiveness due to the cross-linked structure resulting from the reaction between the moisture (water) and isocyanate groups, and has recently attracted attention from various fields as a solvent-free technique. Has been. In the present invention, moisture (water) and water vapor are treated as consent.

  As such a reactive hot melt urethane adhesive, for example, one using an isocyanate group-terminated urethane prepolymer is typically known.

However, when such reactive hot melt urethane adhesives are used in the assembly and manufacture of components for electronic devices, the production line speed is high, so bonding and fixing with reactive hot melt urethane adhesives However, the trouble that the process is shifted to the next process in a state where it is still inadequate frequently occurs, which is a problem in process control and quality control.
Moreover, since it is necessary to maintain a molten state at the time of heat application, the reactive hot melt urethane adhesive generally has a problem of poor heat resistance retention.

  Also, a leather-like sheet having at least a base material layer and a skin layer, wherein the skin layer is 100 parts by mass of a urethane prepolymer, 5 to 40 parts by mass of a colorant containing a polyol as a vehicle, It consists of a crosslinked product of a polyurethane hot melt composition containing 5 to 50 parts by mass of a functional (meth) acrylate and 0.5 to 5 parts by mass of a photopolymerization initiator, and the urethane prepolymer is polytetramethylene glycol. Obtained by reacting 5 to 50% of the number of isocyanate groups in an isocyanate group-containing urethane prepolymer obtained by reacting a polyol containing 40% by mass or more with a polyisocyanate with a hydroxyl group-containing (meth) acrylate A leather-like sheet is known (for example, see Patent Document 4).

  Such leather-like sheets have excellent surface quality by suppressing the fluffing of the skin layer, and are excellent in soft texture, durability and bending resistance. For example, footwear such as women's shoes, sports shoes, sandals, etc. It can also be used as artificial leather and synthetic leather used in the manufacture of furniture and clothing.

  However, since the leather-like sheet of Patent Document 4 places particular emphasis on flexibility, the urethane prepolymer contains only about 5 to 50% of the number of isocyanate groups in the isocyanate group-containing urethane prepolymer. Since it did not react with acrylate, there was a problem that the shape retention after coating was poor.

  As described above, the conventional techniques include shape retention after application to a substrate, flexibility, durability (particularly hydrolysis resistance), substrate adhesion (particularly adhesion to metal), and low outgassing properties. However, the development of an active energy ray-curable hot melt urethane resin composition having a balanced performance, a member for electronic equipment using the same, and packing has been eagerly desired.

  Thus, conventionally, polytetramethylene glycol (PTMG) was generally used as the polyol used in the urethane prepolymer in order to express properties such as flexibility and durability, but initial aggregation is caused by using only PTMG. Since the force was insufficient, the shape retention after application to the substrate was poor.

  Therefore, as a result of various studies, the present inventors have found that an aromatic polyester containing a glycol having a 2,2-dimethyl-1,3-propylene group in an amount of 90 mol% or more in the glycol component for the purpose of improving the initial cohesive force. An active energy ray-curable hot melt urethane resin composition having good performance such as shape retention, flexibility and mechanical strength after application to a substrate by using a polyol and a polyol containing another polyol in combination. Was found and filed (Patent Document 5).

  However, this has a problem in that the compatibility between the aromatic polyester polyol and other polyols (especially polyether polyol) is insufficient, and the properties such as flexibility and mechanical strength are still unsatisfactory.

Japanese Patent Laid-Open No. 2-50378 JP 2009-96839 A Publication No. 99-51653 Japanese Patent No. 4168205 Japanese Patent Application No. 2010-198793

  The object of the present invention is to combine the two characteristics of hot melt properties that are rapidly solidified by cooling after application and fast curability by irradiation with active energy rays such as ultraviolet rays, electron beams, X-rays, infrared rays, and visible rays. Furthermore, the compatibility of polyols can be improved to form a uniform compatible system, so that flexibility, mechanical strength, shape retention after application to a substrate, durability (particularly hydrolysis resistance), substrate An object of the present invention is to provide an active energy ray-curable hot melt urethane resin composition having excellent properties such as adhesion (particularly adhesion to metal) and low outgassing, an electronic device member using the same, and packing.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that the aromatic polyester polyol (a1), the aromatic polyester polyol (a1) and the bisphenol A-containing polyester polyol (a3) described later are not included. By using the bisphenol A-containing polyester polyol (a3) together with the polyol (a2) (especially the polyether polyol), the bisphenol A-containing polyester polyol (a3) acts as an excellent “compatibility agent”. Since the compatibility of (A) can be improved to form a uniform compatible system, it is more flexible and has excellent mechanical strength, shape retention after application to a substrate, durability (especially water resistance) Degradability), substrate adhesion (particularly metal adhesion), low outgassing, etc. It found that it is possible to obtain an active energy ray-curable hot melt urethane resin composition, and have completed the present invention.

  That is, the present invention provides an aromatic polyester polyol (a1) containing a glycol having a 2,2-dimethyl-1,3-propylene group in an amount of 90 mol% or more in the glycol component, other than the above (a1) and the following (a3). Isocyanate group obtained by reacting polyol (A2), polyol (A3) containing polyester polyol (a3) obtained by condensation reaction of alkylene oxide adduct of bisphenol A and polycarboxylic acid, and polyisocyanate (B) Hot-melt urethane (X) in which more than 50% of the total number of isocyanate groups in the terminal urethane prepolymer (C) is 100% or less and the terminal functional group-containing (meth) acrylic compound (D) has terminal (meth) acryloyl groups. And an active energy ray polymerization initiator (Y). It relates sexual energy ray-curable hot melt urethane resin composition.

  The present invention relates to a member for electronic equipment, which is formed by molding the active energy ray-curable hot melt urethane resin composition.

  The present invention relates to a packing formed by molding the active energy ray-curable hot melt urethane resin composition.

  The active energy ray-curable hot melt urethane resin composition of the present invention has a hot melt property that quickly cools and solidifies after application and irradiation with active energy rays such as ultraviolet rays, electron beams, X-rays, infrared rays, and visible rays. It has the two characteristics of fast curing and can improve the compatibility of the polyol to form a uniform compatible system, so that flexibility, mechanical strength, shape retention after application to the substrate, Excellent properties such as durability (particularly hydrolysis resistance), substrate adhesion (particularly metal adhesion), and low outgassing properties. For example, packings (for electronic equipment, industrial parts, and hard disk drives) In addition to electronic equipment members such as various packing for housing cases, cap seal materials, fixing materials (for example, for magnetic heads, for fixing substrates and connectors, etc.) Sealing material, film, sheet, industrial packing, ribbons, adhesives (eg for building materials, such as fibers), coating agents, adhesives are widely useful like.

  The present invention is described in detail below.

  The active energy ray-curable hot melt urethane resin composition of the present invention exceeds 50% of the total number of isocyanate groups in the isocyanate group-terminated urethane prepolymer (C) obtained by reacting the polyol (A) with the polyisocyanate (B). 100% or less of the hot-melt urethane (X) having a terminal (meth) acryloyl group by a reactive functional group-containing (meth) acrylic compound (D) and an active energy ray polymerization initiator (Y) Become.

  The isocyanate group-terminated urethane prepolymer (C) used in the present invention (hereinafter referred to as “urethane prepolymer (C)”) is glycol having 2,2-dimethyl-1,3-propylene group as an essential component. Aromatic polyester polyol (a1) (hereinafter referred to as “aromatic polyester polyol (a1)”) containing 90 mol% or more of the components, and polyol (a2) other than (a1) and the following (a3) (hereinafter referred to as “polyol”). (A2) ") and a polyester polyol (a3) obtained by condensation reaction of an alkylene oxide adduct of bisphenol A and a polycarboxylic acid (hereinafter referred to as" bisphenol A-containing polyester polyol (a3) "). Reaction of polyol (A) and polyisocyanate (B) It is possible to obtain.

  In the present invention, the aromatic polyester polyol (a1) is obtained by a condensation reaction of a glycol and an aromatic carboxylic acid, and a glycol having a 2,2-dimethyl-1,3-propylene group is used as a glycol component. It is an essential condition to contain 90 mol% or more. If the aromatic polyester polyol (a1) contains a glycol having a 2,2-dimethyl-1,3-propylene group in an amount of 90 mol% or more in the glycol component, the initial cohesive force is improved and applied to the substrate. Excellent properties such as subsequent shape retention and mechanical strength can be exhibited. Further, when the aromatic polyester polyol (a1) contains less than 90 mol% of glycol having 2,2-dimethyl-1,3-propylene group in the glycol component, the initial cohesive force is lowered. The shape retention after application to the substrate is poor and the object of the present invention cannot be achieved.

  Examples of the glycol having a 2,2-dimethyl-1,3-propylene group include, for example, neopentyl glycol (NPG), its dimer, trimer, and at least one of these compounds as an initiator. A glycol obtained by ring-opening polymerization of butyrolactone, ε-caprolactone, etc., preferably neopentyl glycol (NPG).

  In the synthesis of the aromatic polyester polyol (a1), in addition to the glycol having 2,2-dimethyl-1,3-propylene group, which is an essential component, other than glycol having 2,2-dimethyl-1,3-propylene group The glycol can be used as the glycol component.

  Examples of glycol components other than the glycol having the 2,2-dimethyl-1,3-propylene group include ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,3-butanediol, , 4-butanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 1,8-octanediol, diethylene glycol, triethylene glycol, dipropylene glycol, tripropylene glycol, cyclohexane-1,4 -1 type, or 2 or more types selected from diol and cyclohexane- 1,4-dimethanol can be used. In addition, addition products in which various alkylene oxides are added to bisphenol A, bisphenol F, hydrogenated bisphenol A, hydrogenated bisphenol F, or the like can also be used. A polymer obtained by ring-opening polymerization of γ-butyrolactone, ε-caprolactone or the like using a low molecular weight polyol as an initiator can also be used.

Moreover, as said aromatic carboxylic acid, the 1 type (s) or 2 or more types selected from the group which consists of (anhydrous) phthalic acid, an isophthalic acid, a terephthalic acid, and a terephthalic acid can be used, for example. Among these, when 90 mol% or more of (phthalic anhydride) is contained in the carboxylic acid component, the cohesion with the glycol having the 2,2-dimethyl-1,3-propylene group improves the initial cohesion. It is preferable because moldability can be improved and appropriate flexibility and excellent mechanical strength can be obtained.

  The number average molecular weight (Mn) of the aromatic polyester polyol (a1) is preferably in the range of 500 to 5000, more preferably in the range of 500 to 3000. If Mn of (a1) is within such a range, excellent characteristics such as mold retention, coating workability, and initial cohesive force can be obtained. When the Mn of (a1) is less than 500, the initial cohesive force is lowered, the shape retention is poor, the heat stability is poor, the cured product is too hard, and the flexibility tends to be poor, which is not preferable. . In addition, when Mn of (a1) exceeds 5000, the viscosity as a polyol is excessively increased, so that the miscibility with the polyol (a2) and the bisphenol A-containing polyester polyol (a3) is inferior. Since the melt viscosity of the urethane prepolymer (C) obtained in this way also greatly increases, it tends to be inferior in workability and is not preferable. The Mn of the aromatic polyester polyol (a1) was measured under the conditions described later.

  Examples of the polyol (a2) other than the aromatic polyester polyol (a1) and the bisphenol A-containing polyester polyol (a3) include polyether polyol, polycarbonate polyol, polyester polyol, acrylic polyol, and the like. You may use the above together. Among these, polyether polyols are preferred because they are durable (particularly hydrolysis resistance) and have excellent flexibility even under a wide range of temperature conditions from low to high temperatures. Among the polyether polyols, polytetramethylene glycol (PTMG) and polypropylene glycol (PPG) are preferable, and PTMG is more preferable.

  In particular, when PTMG is used as the polyol (a2), the Mn of PTMG is preferably in the range of 500 to 3000, more preferably in the range of 1000 to 2000. If the PTMG Mn is within such a range, excellent durability (particularly hydrolysis resistance), flexibility, and mechanical strength can be obtained.

  Next, the bisphenol A-containing polyester polyol (a3) will be described.

  In the present invention, preferably in the range of 20 to 70 parts by mass of the aromatic polyester polyol (a1) and 80 to 30 parts by mass of the polyol (a2) in 100 parts by mass of the total amount of the polyol (A). It contains in the range, More preferably, the said (a1) is contained in the range of 20-50 mass parts, and the said (a2) is contained in the range of 80-50 mass parts. If the polyol (A) contains the (a1) and the (a2) in such a range, good performance such as shape retention, flexibility, and mechanical strength after application to the substrate is exhibited. be able to.

  At that time, the content of the bisphenol A-containing polyester polyol (a3) is preferably in the range of 5 to 50 parts by mass, more preferably in the range of 10 to 30 parts by mass in 100 parts by mass of the total amount of the polyol (A). It is. If the (a3) is contained in such a range, the compatibility between the polyol components contained in the polyol (A) [i.e., the (a1) to (a3)] can be further improved, so that more excellent flexibility. And mechanical strength can be obtained.

  An alkylene oxide adduct of bisphenol A, which is a polyether polyol in which the alkylene oxide is added to bisphenol A, is produced by, for example, adding the alkylene oxide by a well-known and conventional method using the bisphenol A as an initiator. Can do.

  Examples of the alkylene oxide used in the production of the bisphenol A-containing polyester polyol (a3) include ethylene oxide (EO), propylene oxide (PO), butylene oxide (BO), and tetramethylene oxide (THF). Among these, EO and PO are preferable.

  Examples of the alkylene oxide adduct of bisphenol A include, for example, an n-mol adduct of alkylene oxide such as ethylene oxide (EO), propylene oxide (PO), butylene oxide (BO), and tetramethylene oxide (THF) of bisphenol A ( However, n is a number exceeding 0). Among these alkylene oxide adducts of bisphenol A, EO and / or PO of bisphenol A can be maintained because it can maintain an appropriate initial cohesive force with respect to the substrate and can further improve characteristics such as excellent flexibility and heat resistance. 1-10 mol adducts of These may be used alone or in combination of two or more.

  In particular, as the bisphenol A-containing polyester polyol (a3), a polyether polyol obtained by adding 4 to 8 moles of propylene oxide (PO) to the bisphenol A, the aliphatic dicarboxylic acid and the alicyclic dicarboxylic acid. When a product obtained by condensation reaction with an acid is used, the compatibility with each polyol component of the active energy ray-curable hot melt urethane resin composition of the present invention can be further improved, and an appropriate initial value for the substrate can be obtained. The cohesive force can be maintained, and excellent flexibility and durability (hydrolysis resistance) can be expressed, which is preferable.

  Since the bisphenol A-containing polyester polyol (a3) is very compatible with the aromatic polyester polyol (a1) and the polyol (a2), the active energy ray-curable hot melt urethane resin composition of the present invention is cured. Flexibility and mechanical strength can be further improved without impairing performance such as transparency and adhesiveness.

  Moreover, as said polycarboxylic acid, performance, such as compatibility with the said aromatic polyester polyol (a1) and the said polyol (a2), among aliphatic dicarboxylic acid, aromatic dicarboxylic acid, alicyclic dicarboxylic acid, etc. Depending on the situation, it can be appropriately selected and used.

  Examples of the aliphatic dicarboxylic acid include succinic acid, adipic acid, glutaric acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, dodecanedicarboxylic acid, maleic acid, and fumaric acid. In order to improve the initial cohesive force of the resin composition to be used, it is preferable to use a dicarboxylic acid having 6 or more carbon atoms, and more specifically, sebacic acid or dodecanedicarboxylic acid is more preferably used. Examples of the aromatic dicarboxylic acid include orthophthalic acid, isophthalic acid, terephthalic acid, naphthalenedicarboxylic acid, biphenyldicarboxylic acid, 1,2-bis (phenoxy) ethane-p, p′-dicarboxylic acid, and p-hydroxybenzoic acid. , P- (2-hydroxyethoxy) benzoic acid, trimellitic acid, pyromellitic acid and the like. Among these, orthophthalic acid is preferable because of its large initial cohesion. Examples of the alicyclic dicarboxylic acid include 1,3-cyclopentanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid, and the like. Moreover, in order to improve the compatibility and initial cohesion of the target resin composition, it is more preferable to use a dicarboxylic acid having 6 or more carbon atoms and an aromatic dicarboxylic acid in combination.

  Instead of the polycarboxylic acid, various carboxylic acid derivatives such as lower alkyl esters such as methyl ester compounds of polycarboxylic acids, acid anhydrides, and acid halides may be used.

  The number average molecular weight (Mn) of the bisphenol A-containing polyester polyol (a3) is preferably in the range of 500 to 10000, more preferably in the range of 1000 to 7000. If the Mn of (a3) is within such a range, an active energy ray-curable hot melt urethane resin composition capable of forming a cured product having appropriate flexibility according to the purpose can be obtained.

  Thus, in the present invention, by using the bisphenol A-containing polyester polyol (a3) as a “compatibility agent” together with the aromatic polyester polyol (a1) and the polyol (a2), the (a1) to ( Since the three components a3) can form a more uniform compatible system, it is more flexible and can exhibit excellent mechanical strength.

  In the present invention, when polypropylene glycol (PPG) is used as a trifunctional component in this system, the crosslinking density is increased, and durability (particularly hydrolysis resistance) can be further improved without impairing flexibility. it can.

  The content of the PPG at that time is preferably in the range of 0.5 to 5.0 parts by mass, more preferably 1.0 to 3.0 parts per 100 parts by mass of the total amount of the polyol (A). It is the range of mass parts. If the PPG is contained in such a range, good characteristics such as viscosity stability by heat and flexibility can be imparted.

  Next, the polyisocyanate (B) used for production of the isocyanate group-terminated urethane prepolymer (C) will be described below.

  The polyisocyanate (B) used in the present invention is not particularly limited, and conventionally known polyisocyanate (B) can be used. For example, diphenylmethane diisocyanate (MDI; its 4,4′-form, 2,4′-form or 2 , 2 ′ form, or a mixture thereof, crude MDI), carbodiimide-modified MDI (modified MDI), polymethylene polyphenyl polyisocyanate, carbodiimidized diphenylmethane polyisocyanate, xylene diisocyanate, tolylene diisocyanate (TDI; 4 or 2, 6 or a mixture thereof), xylylene diisocyanate (XDI), 1,5-naphthalene diisocyanate (NDI), aromatic diisocyanate such as tetramethylxylene diisocyanate, phenylene diisocyanate, or hexamethyl. Diisocyanate (HDI), dimer acid diisocyanate, norbornene diisocyanate, lysine diisocyanate, aliphatic diisocyanate such as tetramethylxylylene diisocyanate, or isophorone diisocyanate (IPDI), hydrogenated diphenylmethane diisocyanate (hydrogenated MDI), hydrogenated xylylene diisocyanate ( (Hydrogenated XDI), cycloaliphatic diisocyanate such as cyclohexane diisocyanate, dicyclohexylmethane diisocyanate, isophorone diisocyanate and the like. Among these, reactivity with polyol (A) and reaction with moisture (water) are fast, MDI and XDI are preferred. These may be used alone or in combination of two or more.

  In this invention, the said polyol (A) and the said polyisocyanate (B) are made to react, and an isocyanate group terminal urethane prepolymer (C) is synthesize | combined.

  The urethane prepolymer (C) can be reacted by a known and commonly used method, and the reaction method is not particularly limited. If an example of the reaction method is given, the polyol (A) charged in the reaction vessel, that is, the aromatic polyester polyol (a1), the polyol (a2), and the bisphenol A-containing polyester polyol (a3) are essentially included. Water is removed from the polyol mixture in advance under reduced pressure heating conditions, and then the necessary amount of polyisocyanate (B) is charged into the polyol mixture by an appropriate method such as dropwise, divided, batch, or continuous. Then, it can be obtained by a method of reacting until the isocyanate group content (%) becomes substantially constant.

  The urethane prepolymer (C) is usually produced without a solvent, but may be reacted in an organic solvent. When making it react in an organic solvent, it is necessary to select the organic solvent which does not inhibit reaction. Examples of the organic solvent include, but are not limited to, esters such as methyl acetate, ethyl acetate, propyl acetate, and butyl acetate, ketones such as acetone, methyl ethyl ketone, methyl butyl ketone, and cyclohexanone, methyl cellosolve acetate, butyl cellosolve acetate, and the like. Ether esters, aromatic hydrocarbon solvents such as toluene and xylene, and amides such as dimethylformamide and dimethylacetamide. These may be used alone or in combination of two or more. The amount of the organic solvent used is not particularly limited as long as it does not inhibit the reaction. In addition, it is necessary to remove the organic solvent used for the reaction by an appropriate method such as heating under reduced pressure during the reaction or after the completion of the reaction.

  The proportion of the polyol (A) and polyisocyanate (B) used when producing the urethane prepolymer (C) is the hydroxyl group of the isocyanate group of the polyisocyanate (B) and the polyol (A). The equivalent ratio (hereinafter referred to as [NCO / OH equivalent ratio]) is preferably in the range of 1.1 to 5.0, more preferably in the range of 1.5 to 3.0. When the NCO / OH equivalent ratio is in such a range, an active energy ray-curable hot melt urethane resin composition having a melt viscosity suitable for coating and excellent shape retention by cooling and solidification can be obtained.

  Reaction conditions (temperature, time, etc.) for producing the urethane prepolymer (C) may be appropriately set in consideration of various conditions such as safety, quality, cost and the like, and are not particularly limited. The reaction time is preferably in the range of 1 to 5 hours.

  The urethane prepolymer (C) preferably has a softening temperature measured in accordance with Japanese Industrial Standard K 2207 in the range of 30 to 120 ° C, more preferably in the range of 40 to 100 ° C. If the softening temperature of (C) is in such a range, it is preferable because the shape retention after application to the substrate is excellent.

  As a method for preparing the softening temperature of the urethane prepolymer (C) within such an appropriate temperature range, for example, (1) Adjustment by molecular weight (adjustment of the molar ratio of polyol and polyisocyanate, Various methods such as (2) adjustment by the crystallinity of the ethylene chain of the polyester polyol, (3) adjustment by the aromatic structure of the polyol or polyisocyanate, (4) adjustment by urethane bond, etc. Yes, it may be selected as appropriate, and is not particularly limited.

  The active energy ray-curable hot-melt urethane resin composition of the present invention is more than 50% of the total number of isocyanate groups of the urethane prepolymer (C) and preferably 100% or less, preferably 60 to 100%. The active energy ray polymerization initiator (Y) is contained together with the hot melt urethane (X) having a terminal (meth) acryloyl group by the containing (meth) acrylic compound (D).

  Examples of the reactive functional group-containing (meth) acrylic compound (D) include 2-hydroxyethyl (meth) acrylate (HEA), 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 4 -Hydroxybutyl (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate, pentaerythritol triacrylate, etc., among these, for example, ultraviolet rays, electron beams, X-rays, infrared rays, visible rays, etc. Of these, 2-hydroxyethyl acrylate (HEA) is preferable because it is excellent in rapid curability by irradiation with active energy rays and particularly improves mechanical strength. These may be used alone or in combination of two or more.

  In the present invention, the reactive functional group-containing (meth) acrylic compound (D) is added to the total number of terminal NCO groups of the isocyanate group-terminated urethane prepolymer (C) in order to improve the shape retention after application to the substrate. Curing reaction by irradiation with active energy rays such as ultraviolet rays, electron beams, X-rays, infrared rays and visible rays due to double bonds after reacting with more than 100% and less than 100%, and moisture (water) curing reaction with NCO groups In combination, the shape retention after application to the substrate, flexibility, mechanical strength, durability (especially hydrolysis resistance), substrate adhesion (especially adhesion to metals), fast curing Can be improved.

  Specifically, with respect to 100 parts by mass of the urethane prepolymer (C), the reactive functional group-containing (meth) acrylic compound (D) is preferably in the range of 5.0 to 20.0 parts by mass, more preferably. Is added in the range of 5.0 to 15.0 parts by mass, and the reaction is performed in the range of 50% to 100%, preferably 80 to 100% of the total number of isocyanate groups in the urethane prepolymer (C). The hot-melt urethane (X) having a terminal (meth) acryloyl group is obtained from the functional functional group-containing (meth) acrylic compound (D). Next, a predetermined amount of the active energy ray polymerization initiator (Y) is added to the hot melt urethane (X) and stirred to obtain the active energy ray curable hot melt urethane resin composition of the present invention.

  If the isocyanate group of the urethane prepolymer (C) is reacted with the reactive functional group-containing (meth) acrylic compound (D) within such a range, fast curability, shape retention after application to a substrate, Excellent properties such as flexibility, mechanical strength, durability (particularly hydrolysis resistance), and substrate adhesion (particularly adhesion to metal) can be obtained.

  Moreover, when making the said urethane prepolymer (C) and a reactive functional group containing (meth) acrylic compound (D) react, a urethanization catalyst can be used as needed. The urethanization catalyst can be appropriately added at any stage of the urethanization reaction.

  The urethanization reaction is preferably performed until the isocyanate group content (%) becomes substantially constant.

  The urethanization catalyst is not particularly limited, and a conventionally known catalyst can be used. For example, nitrogen-containing compounds such as triethylamine, triethylenediamine, N-methylmorpholine, potassium acetate, zinc stearate, octyl acid An organometallic salt such as monotin or an organometallic compound such as dibutyltin dilaurate can be used.

  The amount of the urethanization catalyst used is not particularly limited as long as it does not adversely affect the safety during the reaction, the stability of the intermediate or product, the quality, and the like.

  Next, the active energy ray polymerization initiator (Y), which is an essential component, will be described below.

  In the active energy ray-curable hot melt urethane resin composition of the present invention, the amount of the active energy ray polymerization initiator (Y) is preferably 0.5 parts relative to 100 parts by mass of the urethane prepolymer (C). It is the range of -5.0 mass parts, More preferably, it is the range of 1.0-3.0 mass parts. If the active energy ray polymerization initiator (Y) is contained in such a range, the curability according to the workability can be adjusted, and as a result, the active energy ray curable hot having excellent shape retention after application to the substrate. A melt urethane resin composition can be obtained.

  The active energy ray polymerization initiator (Y) is added at a time when the reactive functional group-containing (meth) acrylic compound (D) exceeds 50% of the total number of terminal NCO groups of the isocyanate group-terminated urethane prepolymer (C) and is 100. It is preferable to add after reacting with less than%.

  Reaction conditions (temperature, time, etc.) may be appropriately set in consideration of various conditions such as safety, quality, and cost, and are not particularly limited. For example, the reaction temperature is preferably in the range of 80 to 120 ° C., and the mixing time is preferably in the range of 0.5 to 2.0 hours.

  The active energy ray polymerization initiator (Y) is not particularly limited, and examples thereof include a photopolymerization initiator and a peroxide.

  Examples of the photopolymerization initiator include conventionally known photopolymerization initiators such as alkylphenone photopolymerization initiators such as benzophenone, camphorquinone photopolymerization initiators, acylphosphine oxide photopolymerization initiators, and titanocene photopolymerization initiators. Can be used and is not particularly limited. Examples of commercially available photopolymerization initiators (hereinafter referred to as trademarks) include, for example, Quantacure (produced by International Bio-Synthetics), Kaiacure MBP (produced by Nippon Kayaku Co., Ltd.), Esacure BO (Flateri Lamberti) Trigonal 14 (manufactured by Akzo), Irgacure (manufactured by Ciba-Geigy), Darocur (manufactured by the company), Speed Cure (manufactured by the company), Darocur 1173 and Fi-4 mixture (manufactured by Eastman) Etc. These may be used alone or in combination of two or more. Among these, Irgacure 651 capable of imparting excellent curability by irradiation with active energy rays such as ultraviolet rays is preferable.

  Moreover, as a peroxide, conventionally well-known peroxides, such as a ketone peroxide, a peroxy ketal, a hydroperoxide, a dialkyl peroxide, a diacyl peroxide, a peroxydicarbonate, a peroxy ester, can be used, for example. These may be used alone or in combination of two or more. Among these, peroxyesters and peroxydicarbonates are preferable for curing under high temperature conditions of 80 to 120 ° C., and peroxydicarbonate is particularly preferable. Examples of the peroxydicarbonate include di (4-t-butylcyclohexyl) peroxydicarbonate, and commercially available products include peroyl TCP (manufactured by NOF Corporation).

  Further, the active energy ray-curable hot melt urethane resin composition of the present invention can contain porous silica (E).

  The porous silica (E) preferably has an average particle diameter in the range of 2.0 to 10.0 μm and an oil absorption amount in the range of 150 to 300 ml per 100 g, more preferably an average The particle diameter is in the range of 2.0 to 10.0 μm, and the oil absorption per 100 g is in the range of 150 to 350 ml. Provided that the average particle diameter and the oil absorption amount of the porous silica (E) are within such ranges, the melt viscosity with excellent workability and the thixotropy with excellent shape retention after application to the substrate are imparted. Can do.

  The “oil absorption amount” in the present invention is a value measured according to Japanese Industrial Standard K5101.

  The amount of the porous silica (E) is preferably in the range of 0.5 to 10 parts by mass, more preferably 2 with respect to 100 parts by mass of the active energy ray-curable hot melt urethane resin composition. It is the range of 0.0-7.5 mass parts. If the blending amount of the porous silica (E) is within such a range, the melt viscosity becomes moderate and the workability is excellent, and excellent performance such as shape retention and thixotropy after application to the substrate can be imparted. ,preferable.

  Commercially available products of the porous silica (E) include, for example, silicia (hereinafter referred to as a trademark, manufactured by Fuji Silysia Co., Ltd.), fine seal (manufactured by Tokuyama Soda Co., Ltd.), Aerosil (manufactured by Nippon Aerosil Co., Ltd.), ACEMATT ( Degussa Co., Ltd.) and the like. Among these, Silisia 310P (Fuji Silysia Co., Ltd.), Silicia 320 (Company), and Silicia 350 (Company) are preferable because viscosity adjustment is easy. These may be used alone or in combination of two or more.

  In the active energy ray-curable hot melt urethane resin composition of the present invention, various additives can be used in any stage of the production process within the range not departing from the object of the present invention, in addition to the raw materials described above. .

  Examples of such additives include foam stabilizers, antioxidants, defoamers, ultraviolet absorbers, abrasive grains, fillers, pigments, dyes, colorants, thickeners, surfactants, flame retardants, and plasticizers. , Lubricants, antistatic agents, heat stabilizers, tackifiers, curing catalysts, stabilizers, fluorescent brighteners, silane coupling agents, waxes and the like. Further, as necessary, conventionally known thermoplastic resins, thermosetting resins, and the like can be appropriately selected and used as the blending resin within a range not impairing the object of the present invention. In addition, the said additive is only an example, As long as the objective of this invention is not inhibited, the kind and usage-amount are not specifically limited.

Examples of the tackifier include rosin resins, rosin ester resins, hydrogenated rosin ester resins, terpene resins, terpene phenol resins, hydrogenated terpene resins, and C ₅ aliphatics as petroleum resins. Resins, C ₉ aromatic resins, C ₅ and C ₉ copolymer resins, and the like can be used.

  Examples of the plasticizer include dibutyl phthalate, dioctyl phthalate, dicyclohexyl phthalate, diisooctyl phthalate, diisodecyl phthalate, dibenzyl phthalate, butyl benzyl phthalate, trioctyl phosphate, epoxy plasticizer, toluene-sulfoamide, chloroparaffin, adipine Acid esters, castor oil, and the like can be used. Examples include methyl acid phosphate (AP-1) and acrylic surface conditioner (BYK-361N).

  As the stabilizer, for example, hindered phenol compounds, benzotriazole compounds, hindered amine compounds and the like can be used.

  As the filler, for example, silicic acid derivatives, talc, metal powder, calcium carbonate, clay, carbon black and the like can be used.

  Examples of the ultraviolet absorber include benzotriazole compounds represented by methylhydroxyphenylbenzotriazole, butylmethylhydroxyphenylbenzotriazole, dibutylhydroxyphenylbenzotriazole, bis (tetramethylpiperidyl) sebacate, and bis (pentamethyl). And hindered amine compounds such as piperidyl) sebacate.

  The “active energy ray” in the present invention includes, for example, ultraviolet rays, electron beams, X-rays, infrared rays, visible rays, and the like. Among these active energy rays, ultraviolet rays, visible rays, and infrared rays are particularly preferable from the viewpoint of resin curability and prevention of resin deterioration.

  Although the wavelength of an active energy ray is not specifically limited, From a viewpoint of the decomposition efficiency of a polymerization initiator, Preferably it is 200-750 nm, More preferably, it is the range of 200-450 nm.

  When the active energy ray-curable hot melt urethane resin composition of the present invention is cured by, for example, ultraviolet irradiation, for example, a mercury lamp (low pressure, high pressure, ultrahigh pressure, etc.), hydrogen lamp, deuterium lamp, halogen lamp, xenon Various light sources such as a lamp, a carbon arc lamp, a fluorescent lamp, and a He—Cd laser can be used, and among them, a high-pressure mercury lamp is preferable.

The present invention is summarized as follows.
Resin compositions used for HDD packing, etc. include mold retention, flexibility, mechanical strength, durability (especially hydrolysis resistance), and substrate adhesion (especially as a packing function). Adhesiveness to metal), low outgassing properties and the like are required as required characteristics, but none of the conventional resin compositions can satisfy all of these required characteristics in a balanced manner.
Conventionally, for example, in order to obtain flexibility and durability, polytetramethylene glycol (PTMG) is used as a polyol as a synthesis raw material for an isocyanate group-terminated urethane prepolymer. Is insufficient, and there is a problem that the shape retention after application to the substrate is extremely inferior.
Therefore, as a result of various studies, the present inventors have found that an aromatic polyester containing a glycol having a 2,2-dimethyl-1,3-propylene group in an amount of 90 mol% or more in the glycol component for the purpose of improving the initial cohesive force. An active energy ray-curable hot melt urethane resin composition having good performance such as shape retention, flexibility and mechanical strength after application to a substrate by using a polyol and a polyol containing another polyol in combination. Was found and filed (Patent Document 5).
However, this has a problem in that the compatibility between the aromatic polyester polyol and other polyols (especially polyether polyol) is insufficient, and the properties such as flexibility and mechanical strength are still unsatisfactory.
Therefore, in the present invention, as a result of various investigations for the purpose of imparting initial cohesive force, in the polyol (A), together with the aromatic polyester polyol (a1) and the polyol (a2), the bisphenol A-containing polyester polyol ( By using a3) together as a “compatibilizing agent”, the polyol (A) can form a uniform compatibility system, thereby providing excellent flexibility, mechanical strength, and shape retention after application to a substrate. It was found that characteristics such as durability, durability (particularly hydrolysis resistance), and low outgassing properties can be obtained.
It has also been clarified that durability (hydrolysis resistance) can be further improved by using propylene glycol (PPG), which is a trifunctional compound, in combination with this system.

  In the present invention, the reactive functional group-containing (meth) acrylic compound (D) is added to the total number of terminal NCO groups in the isocyanate group-terminated urethane prepolymer (C) in order to improve the shape retention after application to the substrate. By using a curing reaction by irradiation with energy rays such as ultraviolet rays by a double bond after reacting with more than 50% and not more than 100%, and a moisture curing reaction with an NCO group, it is possible to maintain the coating after application to the substrate. Unprecedented excellent effects such as moldability, flexibility, mechanical strength, durability (particularly hydrolysis resistance), substrate adhesion (particularly adhesion to metal), and fast curability can be obtained.

  As described above, the active energy ray-curable hot-melt urethane resin composition of the present invention has a hot-melt property that rapidly cools and solidifies after application, and an activity such as ultraviolet rays, electron beams, X-rays, infrared rays, and visible rays. It has two characteristics: rapid curing by energy beam irradiation, flexibility, mechanical strength, shape retention after application to substrate, durability (especially hydrolysis resistance), substrate adhesion ( Particularly excellent in properties such as adhesion to metal) and low outgassing properties. For example, packings (for example, various packings for electronic equipment, industrial parts, hard disk drives, housing cases, etc.), cap seal materials In addition to components for electronic equipment such as fixing materials (for example, for magnetic heads, fixing substrates and connectors, etc.), sealing materials, films, sheets, industrial packing, ribbons Adhesives (e.g. for building materials, such as fibers), a coating agent, is useful in a wide range such as adhesive.

  Further, the packing comprising the active energy ray-curable hot melt urethane resin composition of the present invention has flexibility, mechanical strength, shape retention after application to a substrate, durability (particularly hydrolysis resistance), base Since it is excellent in properties such as material adhesion (particularly adhesion to metal) and low outgassing properties, it is useful for electronic equipment members, particularly for hard disk drive packing.

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the scope of the present invention is not limited only to these examples.
Further, in the present invention, unless otherwise specified, “part” is “part by mass” and “%” is “mass%”.
The measurement method and evaluation method used in the present invention are as follows.

[Measurement method of melt viscosity of hot melt urethane (X) with isocyanate group-terminated urethane prepolymer (C) and terminal (meth) acryloyl group)
The melt viscosity (mPa · s) of each of the isocyanate group-terminated urethane prepolymers (C) and the terminal (meth) acryloyl groups obtained in Examples and Comparative Examples was measured using a cone plate viscometer (ICI). Manufactured at a measurement temperature of 100 ° C.

[Method for measuring softening temperature of isocyanate group-terminated urethane prepolymer (C)]
The softening temperature (dry bulb softening point) (° C.) of each isocyanate group-terminated urethane prepolymer (C) obtained in the examples and comparative examples is 5 ° C./min in accordance with Japanese Industrial Standard K 2207. The measurement was performed under the following conditions.

[Evaluation method for coating workability]
Hot melt urethane (X) having each terminal (meth) acryloyl group obtained in Examples and Comparative Examples was heated and melted at 100 ° C. and filled into a 600 μm inner diameter syringe, pressure: 0.30 MPa, processing speed: The discharge amount (g) when applied on an aluminum plate under the conditions of 100 mm / second and application time: 10 seconds was evaluated according to the following criteria.
Evaluation criteria for coating workability.
○: More than 0.25 and 0.50 g or less.
(Triangle | delta): It exceeds 0.10 and is 0.25 g or less.
X: 0.10 g or less.

[Method for evaluating shape retention after application to substrate]
Hot melt urethane (X) having each terminal (meth) acryloyl group obtained in Examples and Comparative Examples was heated and melted at 100 ° C. and discharged under the above coating conditions (600 μm inner diameter syringe). It apply | coated on material (the kind of base material: Aluminum plate A1050P).
Next, UV irradiation 30 seconds later [Irradiation condition: Conveyor type UV irradiation apparatus “CSOT-40” set to irradiate 145 mJ / cm ² of UV each time it passes through the apparatus (Nippon Battery Co., Ltd.) Manufactured, using a high-pressure mercury lamp, strength 120 W / cm, conveyor speed 10 m / min, one pass)], and measuring the height (μm) of the molded product after curing with an electron microscope (SEM). It evaluated according to.
Evaluation criteria for shape retention after application to a substrate.
○: More than 580 and 600 μm.
(Triangle | delta): It exceeds 540 and is 580 micrometers or less.
×: 540 μm or less.

[Evaluation method of film flexibility after UV irradiation]
Each active energy ray-curable hot melt urethane resin composition obtained in Examples and Comparative Examples was heated and melted at 100 ° C., and applied to a release paper with a thickness of 200 μm using a knife coater heated to 100 ° C. did.
Next, a conveyor type ultraviolet irradiation device CSOT-40 (made by Nippon Battery Co., Ltd., using a high-pressure mercury lamp) was set so that an ultraviolet irradiation amount of 145 mJ / cm ² was passed through the device once through the coating surface. UV irradiation by passing through the inside once at a strength of 120 W / cm and a conveyor speed of 5 m / min), and then left in a constant temperature and humidity chamber at a temperature of 23 ° C. and a relative humidity of 65% for 3 days to perform a moisture curing reaction. Proceeded. The film formed after standing was peeled from the release paper to obtain a cured film.
In addition, said ultraviolet irradiation amount is the value measured in the wavelength range of 300-390 nm using UV checker UVR-N1 (made by Nippon Battery Co., Ltd.).
Tensillon [manufactured by Shimadzu Corporation, head speed: 300 mm / min] is used for the tensile properties of a test piece obtained by cutting the cured film into a width of 5 mm, a length of 70 mm, and a thickness of 200 μm in accordance with JIS K-7311. ] And evaluated. The flexibility of the cured film was evaluated based on the value of 100% modulus (MPa) of tensile properties according to the following criteria.
Evaluation criteria for film flexibility after curing.
A: 3.0 MPa or less B: More than 3.0 and 4.0 Mpa or less.
(Triangle | delta): More than 4.0 and 8.0 Mpa or less.
X: Exceeds 8.0 Mpa.

[Method for evaluating durability (hydrolysis resistance) of cured film]
The cured film obtained above was left in a constant temperature and humidity chamber set at a temperature of 70 ° C. and a relative humidity of 95% for 5 weeks, and then the tensile strength was measured. The tensile properties of the test piece obtained by cutting the cured film into a width of 5 mm, a length of 70 mm, and a thickness of 200 μm were measured in accordance with JIS K-7311, Tensilon [manufactured by Shimadzu Corporation, head speed = 300 mm / min].
The durability of the cured film was evaluated based on the following criteria for the tensile strength retention rate (%) among the tensile properties after the test.
Evaluation criteria for the durability (hydrolysis resistance) of cured films.
○: 90% or more △: 60 or more and less than 90% ×: less than 60%

[Outgassing evaluation method]
The molded product for which the shape retention after application to the substrate was evaluated was subjected to a heat treatment in a dryer set at a temperature of 120 ° C. for 5 minutes, and then the amount of sample collected: 30 mg, heat desorption conditions: The quantification of the outgas component according to VDA278 (VOC) was measured at 90 ° C. for 30 minutes using GC-MASS.
A value obtained by converting the total of the detected component areas in the retention time until the eicoic acid having 20 carbon atoms into toluene was defined as the VOC value, that is, the outgas amount (ppm).
The outgassing property of the molded product was evaluated based on the VOC value.
Evaluation criteria for outgassing.
○: 10 ppm or less Δ: More than 10 and 40 ppm or less.
X: Over 40 ppm.

[Evaluation method of substrate adhesion]
Tensilon [manufactured by Shimadzu Corp., head] according to JIS K-7311, the peel strength of the molded product applied on the aluminum plate A5052 produced by the method for evaluating the shape retention after application to the base material. Speed = 200 mm / min]. In addition, base-material adhesiveness evaluated the value (N) of peeling strength according to the following references | standards.
Evaluation criteria for substrate adhesion.
○: 2.0 N or more.
Δ: 0.5 or more and less than 2.0N.
X: Less than 0.5N.

[Evaluation method for fast curability]
The presence or absence of a residue on the peeled aluminum plate evaluated by the above-mentioned substrate adhesion was visually observed, and fast curability was evaluated according to the following criteria.
Evaluation criteria for fast curability.
○: No residue remains.
Δ: A state in which a very small amount of residue remains on the surface.
X: A state in which residue remains clearly on the surface.

[Synthesis Example 1]
≪Synthesis of isocyanate group-containing urethane prepolymer (C-1) ≫
In a 1-liter four-necked flask, 55 parts by mass of neopentyl glycol (NPG), 2.0 parts by mass of diethylene glycol (DEG), and 43 parts by mass of phthalic anhydride (OPA) were reacted, and the number average An aromatic polyester polyol (a1-1) having a molecular weight (Mn) of 1,000 and having a 2,2-dimethyl-1,3-propylene group was obtained.
Next, in a 1 liter four-necked flask, 20 parts by mass of the aromatic polyester polyol (a1-1) synthesized above, 70 parts by mass of polytetramethylene glycol (PTMG) (a2-1) having an Mn of 2000, 10 parts by mass of a bisphenol A-containing polyester polyol (a3-1) obtained by reacting sebacic acid and isophthalic acid with a 6-mol propylene oxide (PO) adduct of bisphenol A was heated to 100 ° C. under reduced pressure. Then, dehydration was performed until the moisture content became 0.05% by mass to obtain a polyol (A) as a mixture.
Next, 22 parts by mass of m-xylene diisocyanate is added as polyisocyanate (B) to the polyol (A) cooled to 70 ° C., and the temperature is raised to 100 ° C. until the isocyanate group content becomes constant. It was made to react for 3 hours and the isocyanate group terminal urethane prepolymer (C-1) was obtained.
The urethane prepolymer (C-1) had a melt viscosity at 100 ° C. of 1900 mPa · s and an isocyanate group content (NCO%) of 3.90% by mass. The properties of the urethane prepolymer (C-1) obtained in Synthesis Example 1 are summarized in Table 1.

[Synthesis Examples 2 to 16]
Urethane prepolymers (C-2) to (C-16) were synthesized in the same manner according to the formulation in Table 1.
Properties of urethane prepolymers (C-2) to (C-16) obtained in Synthesis Examples 2 to 16 are summarized in Table 1.

Regarding the aromatic polyester polyol (a1) obtained in Synthesis Examples 1 to 16, the types and compositions of glycols and aromatic carboxylic acids having 2,2-dimethyl-1,3-propylene groups as raw materials are as follows. is there.
(A1-1) Aromatic polyester polyol Composition: NPG / DEG / OPA
Mn: 1000
Glucol: NPG / DEG = 96.6 / 3.4 mol%
Aromatic carboxylic acid: OPA = 100 mol%
(A1-2) Aromatic polyester polyol Composition: NPG / TPA
Mn: 1000
Glucol: NPG = 100 mol%
Aromatic carboxylic acid: TPA = 100 mol%

[Example 1]
≪Synthesis of active energy ray-curable hot melt urethane resin composition (UVHM1) ≫
100 parts by mass of the isocyanate group-containing urethane prepolymer (C-1) obtained in Synthesis Example 1 was heated and melted at 100 ° C., and 2-hydroxyethyl acrylate (HEA) was obtained as the reactive functional group-containing (meth) acrylic compound (D). ) 5.3 parts by mass and 0.01 parts by mass of stannous octylate were reacted at an internal temperature of 80 ° C. until the NCO% became constant, thereby forming a hot melt urethane (X) having a terminal (meth) acryloyl group (X -1) was obtained.
Ratio of the number of NCO groups reacted with HEA as the reactive functional group-containing (meth) acrylic compound (D) with respect to the total number of isocyanate groups of the urethane prepolymer (C-1) [[OH / NCO] × 100 (%)] Was prepared so that the theoretical value of the total number of NCO groups was 55%.
The composition and properties of the hot melt urethane (X-1) are summarized in Table 1. The melt viscosity at 100 ° C. of the hot melt urethane (X-1) was 1920 mPa · s, and the isocyanate group content (NCO%) was 1.93 mass%.
Next, hot melt urethane (X-1) having the terminal (meth) acryloyl group and Irgacure 651 (manufactured by Ciba Specialty Co., Ltd.) 2.0 which is an ultraviolet curing agent as the active energy ray polymerization initiator (Y-1). The active energy ray-curable hot melt urethane resin composition (UVHM1) of the present invention was obtained by mixing and stirring the parts.

  The ratio of the number of NCO groups reacted with the reactive functional group-containing (meth) acrylic compound (D) to the total number of isocyanate groups of the urethane prepolymer (C-1) [[OH / NCO] × 100. (%)], According to a conventional method, adding excess dibutylamine, reacting the isocyanate group with dibutylamine, and then calculating the amount of the remaining dibutylamine by the back titration method using hydrochloric acid. Can be requested.

  For the urethane prepolymers (C-2) to (C-16) in Table 1, the reactive functional group-containing (meth) acrylic compound (D) is reacted in the same manner as in the above (C-1). The ratio of the number of NCO groups formed [[OH / NCO] × 100 (%)] was determined.

[Creation of molded product using active energy ray-curable hot melt urethane resin composition]
The active energy ray-curable hot-melt urethane resin composition (UVHM1) was heated and melted to 100 ° C., and then dispensed with a 0.6 mmφ inner diameter dispenser head heated to 100 ° C., discharge pressure: 0.30 MPa, processing speed Conveyor type set to irradiate 145 mJ / cm ² of ultraviolet rays (UV) every time it passes through the device after being applied in a bead shape on an aluminum plate at 100 mm / second, coating time: 10 seconds. UV irradiation is performed by passing once through the UV irradiation apparatus “CSOT-40” (made by Nippon Battery Co., Ltd., using a high-pressure mercury lamp, strength 120 W / cm, conveyor speed 30 m / min), and then at a temperature of 23 ° C. The molded article 1 after moisture curing was obtained by leaving it in a constant temperature and humidity chamber having a relative humidity of 65% for 3 days. Table 1 shows the characteristic evaluation results of the molded article 1 using the active energy ray-curable hot melt urethane resin composition of the present invention. The molded product 1 has surface tack disappeared after UV irradiation, has appropriate flexibility and mechanical strength, has shape retention after application to a substrate, durability (hydrolysis resistance), low outgassing property It had excellent performance.

[Example 2] and [Example 3]
Example 2 and Example 3 are the same as Example 1 except that the amount of HEA used as the reactive functional group-containing (meth) acrylic compound (D) was changed to 9.9 parts by mass and 13.2 parts by mass, respectively. The same operation was performed to obtain active energy ray-curable hot melt urethane resin compositions (UVHM2) and (UVHM3) of the present invention.
The ratio of the number of NCO groups reacted with HEA as the reactive functional group-containing (meth) acrylic compound (D) with respect to the total number of isocyanate groups of the urethane prepolymer (C-1) [[OH / NCO] × 100 (%)] was prepared so that the theoretical value of the total number of NCO groups was 75% (Example 2) and 100% (Example 3), respectively.
Subsequently, in Example 2 and Example 3, molding after moisture curing using the active energy ray-curable hot melt urethane resin compositions (UVHM2) and (UVHM3) of the present invention in the same manner as in Example 1. Product 2 and molded product 3 were obtained.
The evaluation results of the molded product 2 and the molded product 3 are shown in Table 1. The molded product 2 and the molded product 3 lose surface tack after UV irradiation, have appropriate flexibility and mechanical strength, shape retention after application to a substrate, durability (hydrolysis resistance), It had excellent performance such as low outgassing.

[Example 4] to [Example 17] and [Comparative Example 1] to [Comparative Example 10]
[Example 4] to [Example 17] and [Comparative Example 1] to [Comparative Example 10] were carried out in the same reaction procedure according to the formulations shown in Tables 1 and 2. The urethane prepolymers (C-2) to (C-16), hot melt urethanes (X-4) to (X-23), and active energy ray-curable hot melt urethane resin compositions (UVHM4) to (UVHM4) to ( The evaluation results of UVHM27) are shown in Tables 1 and 2.

[Comparative Example 8]
As an acrylate component, 5 parts 2-ethyl-2-butylpropanediol diacrylate, 95 parts isononyl acrylate, SIBSTAR 072T (trade name, manufactured by Kaneka Corporation, styrene-isobutylene-styrene copolymer having a triblock structure, styrene 35 parts of 23% by weight), 2 parts of Irgacure 651 (manufactured by Ciba Specialty Co., Ltd.) as a photopolymerization initiator, and 6 parts of Aerosil 200 (trade name, Nippon Aerosil Co., Ltd., surface-untreated fumed silica) Part of the mixture was mixed and stirred with a planetary mixer heated to 60 ° C. to obtain an ultraviolet curable resin composition (X-24).
By irradiating the ultraviolet curable resin composition (X-24) with UV in the same manner as in the above Examples and Comparative Examples, flexibility, durability, coating workability, shape retention, outgas measurement, substrate adhesion Evaluation of fast curability was performed. Although the obtained molded product was flexible, it produced a large amount of outgas, and was inferior in substrate adhesion and UV curing after UV curing.

The abbreviations listed in Tables 1 and 2 mean the following compounds.
NPG: neopentyl glycol DEG: diethylene glycol OPA: phthalic anhydride TPA: terephthalic acid PTMG: polytetramethylene glycol actol MN700: trade name, trifunctional propylene glycol (molecular weight 700, manufactured by Mitsui Chemicals, Inc.)
BIS-A + 6PO: propylene oxide 6 mol adduct of bisphenol A PO: propylene oxide SEBA: sebacic acid IPA: isophthalic acid XDI: xylylene diisocyanate MDI: 4,4′-diphenylmethane diisocyanate HEA: 2-hydroxyethyl acrylate 4HBA: 4-hydroxybutyl acrylate HEMA: 2-hydroxyethyl methacrylate PPG: propylene glycol SIBSAR 072T: trade name, manufactured by Kaneka Corporation, styrene-isobutylene-styrene copolymer having a triblock structure, styrene content 23% by weight
Parroyl TCP: Trade name, Nippon Oil & Fat Co., Ltd. Aerosil 200: Trade name, Nippon Aerosil Co., Ltd., surface-untreated fumed silica il gacure 651: Trade name, Ciba Specialty Co., Ltd. Silicia 350: Trade name, Fuji Silysia Corporation Made by company

  The active energy ray-curable hot melt urethane resin composition of the present invention has a hot melt property that quickly cools and solidifies after application and irradiation with active energy rays such as ultraviolet rays, electron beams, X-rays, infrared rays, and visible rays. It has the two characteristics of fast curing and can improve the compatibility of the polyol to form a uniform compatible system, so that flexibility, mechanical strength, shape retention after application to the substrate, Excellent properties such as durability (particularly hydrolysis resistance), substrate adhesion (particularly metal adhesion), and low outgassing properties. For example, packings (for electronic equipment, industrial parts, and hard disk drives) In addition to electronic equipment members such as various packing for housing cases, cap seal materials, fixing materials (for example, for magnetic heads, for fixing substrates and connectors, etc.) Sealing material, film, sheet, industrial packing, ribbons, adhesives (eg for building materials, such as fibers), coating agents, adhesives are widely useful like.

Claims (8)

Aromatic polyester polyol (a1) containing neopentyl glycol in a glycol component of 90 mol% or more, polyol (a2) other than (a1) and (a3), an alkylene oxide adduct of bisphenol A, a polycarboxylic acid, More than 50% of the total number of isocyanate groups in the isocyanate group-terminated urethane prepolymer (C) obtained by reacting the polyisocyanate (B) with the polyol (A) containing the polyester polyol (a3) obtained by condensation reaction of 100 and 100. % Hot-melt urethane (X) having a terminal (meth) acryloyl group by a reactive functional group-containing (meth) acrylic compound (D) and an active energy ray polymerization initiator (Y) Active energy ray-curable hot melt urethane resin composition . Containing pre KiKaoru aromatic polyester polyol (a1) is, there is obtained a glycol component and an aromatic polycarboxylic acid to a condensation reaction, the glycol component is neopentyl glycol 90 mol% or more in the glycol component The activity according to claim 1, wherein the aromatic carboxylic acid component contains 90 mol% or more of at least one selected from the group consisting of (anhydrous) phthalic acid, isophthalic acid, and terephthalic acid. Energy ray-curable hot melt urethane resin composition.
  The active energy ray-curable hot melt urethane resin composition according to claim 1, wherein the polyol (a2) is a polyether polyol.   The active energy ray-curable hot melt urethane resin composition according to claim 1, wherein the polyol (a2) is polytetramethylene glycol.   In the total amount of 100 parts by weight of the polyol (A), the aromatic polyester polyol (a1) 20 to 70 parts by weight, the polyol (a2) 30 to 80 parts by weight, and the bisphenol A-containing polyester polyol (a3) 5 The active energy ray-curable hot melt urethane resin composition according to claim 1, which is a polyol containing ˜50 parts by mass.   The active energy ray-curable hot melt urethane resin composition according to claim 1, wherein the isocyanate group-terminated urethane prepolymer (C) has a softening temperature in the range of 30 to 120 ° C as measured by Japanese Industrial Standard K 2207.   The member for electronic devices formed by shape | molding the active energy ray-curable hot-melt urethane resin composition as described in any one of Claims 1-6.   A packing formed by molding the active energy ray-curable hot melt urethane resin composition according to any one of claims 1 to 6.