JP4878124B2 - Films and sheets formed from an antistatic acrylic resin composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an antistatic acrylic resin composition hardly causing staining of an adherend and decay of antistatic effects, caused by bleeding of an antistatic agent, and hardly damaging the properties and moldability of a film and sheet; and to provide the film and sheet formed out of the antistatic acrylic resin composition. <P>SOLUTION: The antistatic acrylic resin composition is obtained by adding (B) a polymer-type antistatic agent to an acrylic polymer mixture comprising (a1) 10-80 wt.% acrylic resin and (a2) 90-20 wt.% acrylic rubber particles. The film and sheet are formed out of the antistatic acrylic resin composition. The base film for an adhesive tape for dicing is formed out of the antistatic acrylic resin composition, and the base film for an adhesive tape for background is formed out of the antistatic acrylic resin composition. <P>COPYRIGHT: (C)2007,JPO&amp;INPIT

Description

  The present invention relates to an acrylic resin composition having antistatic performance, and a film and a sheet formed from the acrylic resin composition.

  Since various polymer materials generally have high electrical insulation properties and are easily charged and have problems such as dust adhesion, low molecular weight type antistatic agents such as surfactants are added, and dust caused by charging Prevents the adhesion of.

  However, the low molecular weight type antistatic agent exerts its antistatic effect by leaching to the surface, but for that purpose, it is required to have a permanent antistatic performance, or the low molecular weight antistatic agent is covered by the leaching low molecular weight antistatic agent. In applications where contamination of the adhesive is disliked, the low molecular weight antistatic agent cannot be used.

As an application in which contamination by such a low molecular weight type antistatic agent is disliked, an adhesive tape for semiconductor manufacturing process and the like can be mentioned.
On the other hand, in recent years, high-performance semiconductor chips have been designed to reduce power consumption and to operate at high speed. However, due to the reduction in driving voltage and the omission of protection circuits, they are more susceptible to electrostatic breakdown. For this reason, it has become difficult to obtain sufficient reliability with conventional electrostatic countermeasure equipment such as various ionizers, and antistatic performance to the adhesive tape itself has been required.

  Examples of adhesive tapes for semiconductor manufacturing processes include dicing adhesive tapes and back grind adhesive tapes. The dicing tape is used to fix a semiconductor wafer when the semiconductor wafer formed in a thin disk shape is cut and separated into small chips (this is referred to as “dicing”). The backgrinding adhesive tape is for protecting the pattern surface and holding the semiconductor wafer thinned by polishing in the backgrinding process for polishing the semiconductor wafer on which the pattern is formed.

  Low molecular weight in semiconductor manufacturing process films where permanent contamination is a problem, such as substrate films for dicing adhesive tapes and backgrind adhesive tapes, and applications that require permanent antistatic functions It is required that contamination due to leaching of the mold antistatic agent and attenuation of antistatic performance do not occur.

  As a method of satisfying the above requirements, a method of adding a polymer antistatic agent to a thermoplastic synthetic resin such as olefin is adopted, and polyether ester amide or the like is used as the polymer antistatic agent ( (See Patent Documents 1 and 2). However, since the compatibility between the thermoplastic synthetic resin such as olefin and the polyether ester amide is poor, a method of using an acid-modified polyolefin in combination is known. However, in this method, the polyether ester amide is difficult to be oriented, so that an energization circuit cannot be formed effectively, and a sufficient antistatic effect cannot be obtained with a small amount of addition. Therefore, it is necessary to add a large amount of a polymer type antistatic agent such as polyether ester amide. As a result, problems such as deterioration of molding processability such as roll adhesion during processing and deterioration of mechanical properties of finished films and sheets have been caused.

  In particular, when molding films and sheets by the calendering method, the peelability from the calender roll is important for the molding process, but a composition to which an antistatic agent having an antistatic effect is obtained is added to the calendering method. If it is molded, there is a fatal problem that it cannot adhere to the calendar roll and cannot be molded.

  In addition, since dicing adhesive tapes require performance such as chipping and expandability, there is a problem that these properties are reduced by adding a large amount of a high molecular weight antistatic agent, and it is generally used. Not.

  In dicing, a wafer is cut into a predetermined size by rotating a round blade called a rotating blade at high speed. However, when the wafer is diced in this way, a crack called chipping occurs on the back surface of the wafer due to vibration or impact. In recent years, thinning of wafers has progressed, and chipping has caused a problem that the strength of semiconductor chips is greatly reduced and the yield is greatly reduced. Therefore, the base film of the adhesive tape is required to absorb chipping and vibration and impact during dicing.

  Further, there is an expanding step after dicing, and the adhesive tape attached to the cut chips is stretched to widen the distance between the chips to facilitate chip pickup. Therefore, if the pressure-sensitive adhesive tape is not uniformly stretched in this expanding step, it will lead to a pick-up mistake when picking up the chip, and the yield rate in the manufacture of semiconductor elements will be reduced. Therefore, the base film of the adhesive tape is required to be stretched uniformly.

  In this way, dicing adhesive tape is required to have moderate vibration and shock absorption to prevent chipping and uniform stretchability when expanding, and furthermore, a polymer type antistatic agent with little contamination to the semiconductor chip is required. There is a need for a substrate film used.

  In addition, in the back grinding process, in addition to the fact that a wafer made of silicon, gallium, arsenic or the like is originally brittle, there is unevenness due to the fact that it is thinly polished and further has a pattern formed on one side. As a result, the problem that the wafer is damaged due to an external force applied during polishing of the wafer often occurs.

  Thus, there is a demand for a base film using a polymer-type antistatic agent with less vibration and shock absorption during polishing and less contamination of the semiconductor chip for the backgrind adhesive tape.

JP-A-1-016234 JP-A-3-290464

  The present invention is intended to solve the above-mentioned problems, and is an antistatic acrylic type which is less contaminated on the adherend due to leaching of the antistatic agent and less attenuated in the antistatic effect, and has excellent physical properties and molding processability. It aims at providing a resin composition, a film, and a sheet | seat.

A polymer antistatic agent (B) is added to an acrylic polymer mixture (A) composed of 10 to 60% by weight of acrylic resin (a1) and 90 to 40% by weight of acrylic rubbery particles (a2). antistatic acrylic resin composition characterized in that it does not add an antistatic agent is a surfactant with made and that the films and sheets of the present invention is formed from the antistatic acrylic resin composition characterized, also, be characterized by further base film of back grinding adhesive tape for dicing adhesive tape of the substrate film or the invention of the present invention is formed from the antistatic acrylic resin composition The

  According to the antistatic acrylic resin composition of the present invention, sufficient antistatic performance can be obtained even by adding a small amount of a high molecular weight antistatic agent, and antistatic performance over time due to leaching like a low molecular weight antistatic agent. Can be prevented and contamination of the adherend can also be prevented.

Furthermore, since the film or sheet of the present invention is formed from the above antistatic acrylic resin composition, it has excellent physical properties and molding processability, and can be produced at low cost.
Moreover, since the base film for the adhesive tape for dicing and the adhesive tape for back grinding of the present invention is formed from the antistatic acrylic resin composition, it has sufficient antistatic performance and low contamination, The film has both vibration and shock absorption and uniform stretchability.

Hereinafter, preferred embodiments of the present invention will be described in detail.
The ratio of the acrylic resin (a1) and acrylic rubber-like particles (a2) used in the present invention is from 10 to 80% by weight of acrylic resin (a1) and 90 to 20% by weight of acrylic rubber-like particles (a2). In order to obtain antistatic performance with the addition of a smaller amount of antistatic agent, 10 to 50% by weight of acrylic resin (a1) and 90 to 50% by weight of acrylic rubbery particles More preferably (a2).

  When the acrylic resin (a1) is larger than 80% by weight, it becomes difficult to obtain an antistatic effect by adding a small amount, and when the acrylic resin (a1) is less than 10% by weight, the molding processability is deteriorated or the finished film, The rigidity of the sheet will be insufficient.

  The ratio of the acrylic polymer mixture (A) to the polymer antistatic agent (B) is not particularly limited, but the polymer antistatic agent (B) is 5% in 100% by weight of the antistatic acrylic composition. %, The antistatic performance is sufficiently obtained, and if it is 25% by weight or less, there is little influence on the workability and mechanical properties, so 5% by weight or more and 25% by weight or less are preferable, and more preferable. Is 7 wt% or more and 20 wt% or less.

  The acrylic resin (a1) in the acrylic polymer mixture (A) used in the present invention is not particularly limited, and examples thereof include polymethyl methacrylate and methyl methacrylate-styrene copolymer. The acrylic rubber-like particles (a2) are not particularly limited, but are formed from a monomer mixture comprising an acrylic ester, a polyfunctional monomer copolymerizable therewith, and other monofunctional monomers. Examples thereof include a resin composition including a layer having rubber elasticity.

  Specific examples of the acrylate ester forming the acrylic rubber-like particles (a2) include methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, s-butyl acrylate, t- Esters of acrylic acid such as butyl acrylate, pentyl acrylate, hexyl acrylate, octyl acrylate, 2-ethylhexyl acrylate, dodecyl acrylate, octadecyl acrylate and the like and a C1-C18 saturated aliphatic alcohol; acrylic acid such as cyclohexyl acrylate and C5 or C6 Esters with alicyclic alcohols; Esters with acrylic acids such as phenyl acrylate and phenols; Acrylic acids such as benzyl acrylate and aromatic acids Examples include esters with lecol.

  The polyfunctional monomer used to form the acrylic rubber-like particle (a2) is a monomer having two or more carbon-carbon double bonds in the molecule. For example, acrylic acid, methacrylic acid, Ester of unsaturated monocarboxylic acid such as acid and cinnamic acid and unsaturated alcohol such as allyl alcohol and methallyl alcohol; diester of unsaturated monocarboxylic acid and glycol such as ethylene glycol, butanediol and hexanediol; Examples include esters of dicarboxylic acids such as phthalic acid, terephthalic acid, isophthalic acid, maleic acid and the above-mentioned unsaturated alcohols. Specifically, allyl acrylate, methallyl acrylate, allyl methacrylate, methallyl methacrylate, Allyl cinnamate, methallyl cinnamate, diallyl maleate, diallyl phthalate, di-terephthalate Examples include allyl, diallyl isophthalate, divinylbenzene, ethylene glycol di (meth) acrylate, butanediol di (meth) acrylate, and hexanediol di (meth) acrylate. Of these polyfunctional monomers, allyl methacrylate is particularly preferred. The “di (meth) acrylate” means a generic name of “diacrylate” and “dimethacrylate”.

  In addition to the acrylic ester and polyfunctional monomer that form the acrylic rubber-like particles (a2), other monofunctional monomers copolymerizable with the acrylic ester can be used in combination. Examples of the other monofunctional monomers include methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, pentyl methacrylate, hexyl methacrylate, octyl methacrylate, 2-ethylhexyl methacrylate, and dodecyl methacrylate. , Esters of methacrylic acid such as myristyl methacrylate, palmityl methacrylate, stearyl methacrylate, and behenyl methacrylate with C1-C22 saturated aliphatic alcohols; esters of methacrylic acid such as cyclohexyl methacrylate with C5 or C6 alicyclic alcohols; phenyl Esters of methacrylic acid such as methacrylate and phenols, such as benzyl methacrylate Typical examples include methacrylic acid esters such as esters of phosphoric acid and aromatic alcohol, but also styrene, α-methylstyrene, 1-vinylnaphthalene, 3-methylstyrene, 4-propylstyrene, 4-cyclohexyl. Aromatic vinyl monomers such as styrene, 4-dodecylstyrene, 2-ethyl-4-benzylstyrene, 4- (phenylbutyl) styrene, and halogenated styrene; vinyl cyanide monomers such as acrylonitrile and methacrylonitrile Body; butadiene, isoprene, 2,3-dimethylbutadiene, 2-methyl-3-ethylbutadiene, 1,3-pentadiene, 3-methyl-1,3-pentadiene, 2-ethyl-1,3-pentadiene, 1, 3-hexadiene, 2-methyl-1,3-hexadiene, 3,4-dimethyl-1,3-hex Examples thereof include conjugated diene monomers such as sadiene, 1,3-heptadiene, 3-methyl-1,3-heptadiene, 1,3-octadiene, cyclopentadiene, chloroprene, and myrcene.

  The average particle diameter of the acrylic rubber-like particles (a2) of the acrylic polymer mixture (A) in the present invention is not particularly limited, but is preferably 150 nm or less from the viewpoint of transparency and moldability during film production. Preferably it is the range of 80 nm-120 nm.

  The polymer-type antistatic agent (B) used in the present invention is not particularly limited, but a block copolymer comprising a hydrophilic block and a hydrophobic block is preferable in that antistatic performance can be obtained by adding a small amount. .

  A block copolymer consisting of a hydrophilic block and a hydrophobic block is a block copolymer in which a hydrophilic block and a hydrophobic block are alternately and repeatedly bonded through bonds such as ester bonds, imide bonds, amide bonds, ether bonds, and urethane bonds. Yes, examples of the hydrophobic block include polyolefin, and examples of the hydrophilic block include polyether, polyether-containing hydrophilic polymer, cationic polymer, and anionic polymer.

  As the polyether, polyether diol, polyether diamine, and modified products thereof can be used. The polyether-containing hydrophilic polymer includes a polyether ester amide having a polyether diol segment as a polyether segment forming component, a polyether amide imide having a polyether diol segment, and a polyether having a polyether diol segment. Ester, polyether amides having the same polyether diamine segment, and polyether urethanes having the same polyether diol or polyether diamine segment can be used. As the cationic polymer, a cationic polymer having a cationic group in the molecule can be used. Examples of the cationic group include groups having a quaternary ammonium salt and a phosphonium salt. As the anionic polymer, an anionic polymer having a dicarboxylic acid having a sulfonic acid group and a diol or polyether as essential constituent units and having 2 to 80 sulfonic acid groups in the molecule can be used.

  Furthermore, in the antistatic acrylic resin composition of the present invention, conventionally known ultraviolet absorbers such as benzophenone, benzoate, benzotriazole, cyanoacrylate, hindered amine, silica, Fillers such as clay, calcium carbonate, barium sulfate, glass beads, and talc, flame retardants, antibacterial agents, fungicides, and the like can be appropriately blended.

  The antistatic acrylic resin composition of the present invention can be used in the form of a film or a sheet. It is possible to cope with various hardnesses by changing the ratio of the acrylic resin (a1) and the acrylic rubber particles (a2) of the acrylic polymer mixture of the present invention. Furthermore, since the antistatic acrylic resin composition has transparency, it can be suitably used for applications requiring transparency.

  Films and sheets formed from the antistatic acrylic resin composition of the present invention are based on industrial applications such as masking tapes and marking films, semiconductor manufacturing applications such as dicing adhesive tapes and backgrinding adhesive tapes, and protective films. It can be widely used for material films and sheets, and has a sufficient antistatic effect by adding a small amount of a polymeric antistatic agent that has impact and vibration absorption, uniform stretchability, and is less contaminated by low molecular weight compounds. Since it is obtained, it can be suitably used for semiconductor manufacturing applications.

  Here, as the base film of the adhesive tape for dicing, the acrylic polymer mixture is preferably 10 to 40% by weight of acrylic resin (a1) and 90 to 60% by weight of acrylic rubbery particles (a2). In addition, the value of tan δ at 10 ° C. or more and 40 ° C. or less is preferably set to 0.1 or more. By selecting the above range, vibration can be absorbed more efficiently, and the slope does not become negative at any point on the stress-strain curve in the tensile test of the film, and the film is stretched more uniformly. Will be able to.

  The base film of the adhesive tape for back grinding is preferably 10 to 60% by weight of acrylic resin (a1) and 90 to 40% by weight of acrylic rubber-like particles (a2). The value of tan δ used as an index at 10 ° C. or more and 40 ° C. or less is preferably 0.1 or more. By selecting the above range, vibration and impact can be effectively absorbed.

  The above tan δ measures the temperature dependence of the storage elastic modulus (E ′) and the loss elastic modulus (E ″) at a frequency of 10 Hz and a heating rate of 4 ° C./min using a solid dynamic viscoelasticity measuring device. ”/ E ′. tan δ indicates how much energy the material absorbs when a force is applied to the material, and the larger the value of tan δ, the more energy is absorbed and the repulsion against impact becomes smaller.

  The stress-strain curve in the tensile test of the base film can be created by punching the base film to a width of 19 mm and a length of 150 mm to obtain a test piece, and performing the test at a chuck distance of 50 mm and a tensile speed of 200 mm / min.

  Moreover, the film and sheet | seat formed from the antistatic acrylic resin composition of this invention can be used by a single layer and a multilayer. If the required characteristics are satisfied with a single layer, the use of a single layer is preferable because the manufacturing cost can be reduced. When the required performance cannot be satisfied with a single layer, it can be used with multiple layers. Specifically, two or more layers of a layer made of an antistatic acrylic resin composition and a layer made of a synthetic resin composition, or one or more types of synthesis above and below a layer made of an antistatic acrylic resin composition A three-layer structure in which layers composed of a resin composition are laminated, or a three-layer structure in which layers are laminated from two different synthetic resin compositions on a layer composed of an antistatic acrylic resin composition can also be used. Further, these three-layer structures may be further laminated to have a layer structure of four or more layers.

  The synthetic resin composition used here is not particularly limited, and examples thereof include olefin resins, styrene resins, acrylic resins, ABS, MBS, polyurethane, polyester, polyimide, polyamide, natural rubber, and synthetic rubber.

  The molding of the film or sheet comprising the antistatic acrylic resin composition of the present invention is not particularly limited, but methods such as an extrusion molding method, a calendar molding method, and an inflation molding method can be used.

  When a multilayer film or sheet is produced, a multilayer T-die extrusion method is used as a molding method. However, if the required performance is satisfied with a single-layer film or sheet, general T-die extrusion molding or calendering can be applied. Among them, if production can be performed by calendering, the advantages of high-speed production can be utilized. , It becomes more advantageous in terms of cost. Calender molding is a molding method in which a molten resin is rolled with a heated metal roll (calendar roll) to produce a sheet or film of a desired thickness. Films and sheets having good thickness accuracy and excellent quality can be produced relatively easily. In addition, since the molding speed is fast and the productivity is excellent, it is a molding method suitable for producing a large amount of products of the same standard.

  In particular, when a film or sheet is produced by a calendar molding method, it is preferable to add an additive such as an antioxidant or a release agent (lubricant) for peeling the molten resin from the metal roll to the resin. Although it does not specifically limit as a lubricant to add, A metal soap type compound, an amide type compound, an ethylenebisamide type compound, a polyethylene wax, etc. can be used. Preferably, from the viewpoint of more excellent releasability, for example, fatty acids having 21 or more carbon atoms such as behenic acid and montanic acid, amide compounds such as stearic acid amide, oleic acid amide, erucic acid amide, ethylene bisstearin Ethylene bisamide compounds such as acid amide, ethylene bisoleic acid amide, ethylene biserucic acid amide, diesters of montanic acid and ethylene glycol, ester compounds such as polymer composite esters, zinc stearate, zinc behenate, behenic acid Examples thereof include metal soaps such as magnesium and polyethylene waxes.

  On the other hand, when the base film is used for applications such as an adhesive tape for wafer dicing and an adhesive tape for back grinding, the types and amounts of additives that can be blended are limited. Specifically, phosphorus-containing compounds and substances from which metals and metal ions are liberated are not recommended because they are likely to migrate from the base film and contaminate the wafer surface. When added, it is limited to the amount extracted under certain extraction conditions. Suitable lubricants include, for example, fatty acids having 21 or more carbon atoms such as behenic acid and montanic acid, stearic acid amides, oleic acid amides, erucic acid amides and other amides in view of the fact that they can be peeled off from a high-temperature metal roll. Compounds, ethylene bis stearic acid amide, ethylene bis oleic acid amide, ethylene bis amide acid compounds such as ethylene bis erucic acid amide, diesters of montanic acid and ethylene glycol, ester compounds such as polymer composite esters, zinc stearate, Examples thereof include metal soaps such as zinc behenate and magnesium behenate, and polyethylene wax. Examples of suitable antioxidants include hindered phenol compounds, thioether compounds, amine compounds, and lactone compounds.

  In addition, when producing a film or sheet by an extrusion molding method, compared to the calendar molding method, the high temperature molten resin is less likely to come into contact with the outside air, and the molten resin does not come into contact with the high temperature metal roll. In general, an antioxidant is not added more than that already added to the resin pellet, and no lubricant is added. Therefore, although it is easier than the calendar molding method in terms of film and sheet processing, the production speed is slower than that of the calendar molding method.

When the film or sheet is produced by either the calendar molding method or the extrusion molding method, the thickness is not particularly limited, but a thickness according to the use may be selected as appropriate, but a thickness of 20 μm to 2000 μm is suitable. is there. If it is less than 20 μm or thicker than 2000 μm, processing becomes difficult, which is not preferable.
In the base film of the pressure-sensitive adhesive tape for dicing and the base film of the pressure-sensitive adhesive tape for back grinding, a thickness of 70 μm to 500 μm is suitable. When the thickness is less than 70 μm, there is no rigidity, and workability when applying an adhesive to the base film or sticking to a wafer is inferior. However, if it is thicker than 500 μm, the transparency is lowered and the visibility of the dicing state is deteriorated, and the material cost is increased.

  Moreover, when producing the film or sheet of the present invention, a simple mixture of resin pellets and additives may be used as a material, or a material previously melt-kneaded by a kneader. Furthermore, the additive is blended with the resin at a high concentration. Usually, a material called a master batch is prepared in advance, and these may be simply mixed, or a resin pellet and a master batch may be melt-kneaded. . As a kneading machine used here, a known apparatus can be used, but a roll that can be easily handled and uniformly dispersed, a single or twin screw extruder, a kneader, a kneader, a planetary mixer, a Banbury mixer, etc. Preferably used.

  Next, the present invention will be described in more detail with specific examples, but the present invention is not limited to these examples.

<Example 1>
As the acrylic polymer mixture (A), Parapet SA-FW001 (manufactured by Kuraray Co., Ltd.) comprising 20% by weight of acrylic resin (a1) and 80% by weight of acrylic rubber particles (a2) (hereinafter referred to as [A1]) .) Is 64 parts by weight, 50% by weight of acrylic resin (a1) and 50% by weight of acrylic rubber particles (a2) Parapet GR-F (manufactured by Kuraray Co., Ltd.) (hereinafter referred to as [A2]. ) 16 parts by weight, 20 parts by weight of Pelestat 300 (manufactured by Sanyo Kasei Kogyo Co., Ltd.) (hereinafter referred to as [B1]) as a polymer type antistatic agent, and antioxidant AO-60 (manufactured by Asahi Denka Co., Ltd.) ) 0.1 parts by weight and 0.3 parts by weight of lycowax E (manufactured by Clariant Japan), which is a montanic acid ester as a lubricant, were dry blended and then kneaded with a Banbury mixer and set at 180 ° C. To obtain a film having a thickness of 100μm at Nda molding machine. The evaluation results of the obtained film are shown in Table 1.
As is clear from Table 1, Example 1 has excellent antistatic performance, moldability, evaluation by tensile test, and evaluation by tan δ, and industrial uses such as masking tape and marking film, adhesive tape for dicing, back It can be used for semiconductor manufacturing applications such as grinding adhesive tapes, base films such as protective films, and sheets.

<Example 2>
As an acrylic polymer mixture (A), [A1] is 72 parts by weight and [A2] is 18 parts by weight. As a polymer-type antistatic agent, Pelestat 303 (manufactured by Sanyo Chemical Industries) (hereinafter referred to as [B2]). ) Was 10 parts by weight, and a film having a thickness of 100 μm was obtained in the same manner as in Example 1. The evaluation results of the obtained film are shown in Table 1.
As is clear from Table 1, Example 2 also has excellent antistatic performance, moldability, evaluation by tensile test, and evaluation by tan δ. Industrial applications such as masking tape and marking film, adhesive tape for dicing, back It can be used for semiconductor manufacturing applications such as grinding adhesive tapes, base films such as protective films, and sheets.

<Example 3>
As the acrylic polymer mixture (A), [A1] 89.5 parts by weight and acrylic resin 100% by weight GF (manufactured by Kuraray Co., Ltd.) (hereinafter referred to as [A3]) 9.5 parts by weight, A film having a thickness of 100 μm was formed in the same manner as in Example 1 except that 5 parts by weight of perestat 230 (manufactured by Sanyo Kasei Kogyo Co., Ltd.) (hereinafter referred to as [B3]) was used as the polymer antistatic agent. Obtained. The evaluation results of the obtained film are shown in Table 1.
As is clear from Table 1, Example 3 also has excellent antistatic performance, moldability, evaluation by tensile test, and evaluation by tan δ, and industrial applications such as masking tape and marking film, adhesive tape for dicing, back It can be used for semiconductor manufacturing applications such as grinding adhesive tapes, base films such as protective films, and sheets.

<Example 4>
The thickness of the acrylic polymer mixture (A) was the same as in Example 1, except that [A1] was 72 parts by weight and [A3] was 18 parts by weight, and the polymer type antistatic agent was [B1] 10 parts by weight. A film having a thickness of 100 μm was obtained. The evaluation results of the obtained film are shown in Table 1.
As is clear from Table 1, Example 4 is inferior in terms of evaluation by a tensile test and unsuitable for a dicing adhesive tape for use in semiconductor manufacturing, but antistatic performance, moldability, and tan δ of other evaluation items. Is excellent, and can be used for industrial applications such as masking tapes and marking films, semiconductor manufacturing applications such as pressure-sensitive adhesive tapes for backgrinding, substrate films such as protective films, and sheets.

<Example 5>
As in Example 1, except that the acrylic polymer mixture (A) is [A1] 36 parts by weight and [A3] 54 parts by weight and the polymer antistatic agent is [B1] 10 parts by weight. A film having a thickness of 100 μm was obtained. The evaluation results of the obtained film are shown in Table 1.
As is clear from Table 1, Example 5 is inferior in terms of evaluation by a tensile test and evaluation by tan δ, and is not suitable for a dicing adhesive tape or a back grind adhesive tape for use in semiconductor manufacturing. The antistatic performance and formability of the items are excellent, and it can be used for industrial films such as masking tapes and marking films, and base films and sheets such as protective films.

Judgment on the quality of each evaluation item was in accordance with the following criteria.
[Evaluation of antistatic performance]
Cut the film and sheet into 100mm squares, measure the surface resistivity using a super high resistance meter (Advantest R8340A) at a constant temperature of 63% RH at a temperature of 20 ° C. And evaluated.
Evaluation criteria A: Surface specific resistance value is less than 10 ¹⁰ Ω ○: Surface specific resistance value is 10 ¹¹ or more and less than 10 ¹⁴ Ω ×: Surface specific resistance value is 10 ¹⁴ Ω or more
[Evaluation of formability]
In processing with a calendar roll, the adhesiveness to the roll was evaluated according to the following criteria.
Evaluation criteria ○: Easy peeling.
X: Adhered to the roll and cannot be peeled off.
[Evaluation by tensile test]
A test piece having a width of 19 mm and a length of 150 mm was prepared for the film and sheet, the test was performed at a tensile speed of 200 mm / min, and the inclination at an arbitrary point was evaluated from the obtained stress-strain curve.
Evaluation criteria ○: In the stress-strain curve, the slope at an arbitrary point does not become negative.
X: In the stress-strain curve, there is a point where the slope becomes negative.
[Evaluation by tan δ]
tan δ measures the temperature dependence of the storage elastic modulus (E ′) and loss elastic modulus (E “) at a frequency of 10 Hz and a heating rate of 4 ° C./min using a solid dynamic viscoelasticity measuring device, and the equation tan δ = E“ / E '. The tan δ from 10 ° C. to 40 ° C. was evaluated according to the following criteria.
Evaluation criteria A: tan δ in the range of 10 ° C. or higher and 40 ° C. or lower is 0.2 or higher ○: tan δ in the range of 10 ° C. or higher and 40 ° C. or lower is 0.1 or higher X: tan δ in the range of 10 ° C. or higher and 40 ° C. or lower is 0 Less than 1

<Comparative Example 1>
A film having a thickness of 100 μm was obtained in the same manner as in Example 1, except that [A3] was 90 parts by weight as the acrylic polymer mixture (A) and [B1] was 10 parts by weight as the polymer antistatic agent. The evaluation results of the obtained film are shown in Table 2.
It can be seen that Comparative Example 1 does not provide sufficient antistatic performance.

<Comparative example 2>
A film having a thickness of 100 μm was obtained in the same manner as in Example 1 except that 70 parts by weight of [A3] as the acrylic polymer mixture (A) and 30 parts by weight of [B1] as the polymer antistatic agent were used. The evaluation results of the obtained film are shown in Table 2.
In Comparative Example 2, sufficient antistatic performance was obtained, but there was a problem in moldability due to adhesion to the roll.

<Comparative Example 3>
Example 1 except that [A1] is 19.8 parts by weight and [A2] is 79.2 parts by weight as the acrylic polymer mixture (A), and [B1] is 1 part by weight as the polymer antistatic agent. Similarly, a film having a thickness of 100 μm was obtained. The evaluation results of the obtained film are shown in Table 2.
It can be seen that Comparative Example 3 does not provide sufficient antistatic performance.

<Comparative example 4>
EG8003 (manufactured by Dow Chemical Co., Ltd.) (hereinafter referred to as [C1]), which is an olefin resin, instead of the acrylic polymer mixture (A) (90 parts by weight) and 10% by weight as a polymer type antistatic agent [B1] A film having a thickness of 100 μm was obtained in the same manner as in Example 1 except that. The evaluation results of the obtained film are shown in Table 2.
It can be seen that Comparative Example 4 does not provide sufficient antistatic performance.

<Comparative Example 5>
A film having a thickness of 100 μm is obtained in the same manner as in Example 1 except that [C1] is 70 parts by weight and [B1] is 30 parts by weight as a polymer type antistatic agent instead of the acrylic polymer mixture (A). It was. The evaluation results of the obtained film are shown in Table 2.
In Comparative Example 5, sufficient antistatic performance was obtained, but there was a problem in moldability due to adhesion to the roll.

The antistatic acrylic resin composition according to the present invention can provide sufficient antistatic performance by adding a small amount of a polymeric antistatic agent, and further, the antistatic performance can be reduced due to leaching of the antistatic agent. Since there is no contamination and it is excellent in moldability and physical properties, it can be widely used in the film and sheet fields.

Claims (1)

A polymer antistatic agent (B) is added to an acrylic polymer mixture (A) composed of 10 to 60% by weight of acrylic resin (a1) and 90 to 40% by weight of acrylic rubbery particles (a2). And a base film of a pressure-sensitive adhesive tape for dicing or a pressure-sensitive adhesive tape for back grinding, which is formed from an antistatic acrylic resin composition, wherein an antistatic agent that is a surfactant is not added.