JP4575209B2 - UV curable adhesive composition - Google Patents

Description

  The present invention relates to an ultraviolet curable pressure-sensitive adhesive composition that exhibits adhesive strength upon irradiation with ultraviolet rays.

  Adhesives using (meth) acrylic polymers are used in various fields including building materials, labels, and optical materials. Conventionally, as these pressure-sensitive adhesives, so-called solvent-type pressure-sensitive adhesives in which a (meth) acrylic polymer is dissolved in an organic solvent have been mainstream. This solvent-type pressure-sensitive adhesive is a type of pressure-sensitive adhesive in which a solvent component is volatilized by heating and an adhesive force is expressed.

  Although such a solvent-type pressure-sensitive adhesive has advantages such as good adhesion and high durability, VOC (Volatile Organic Compound) is generated when used. There was a problem. In particular, in recent years, interest in environmental issues and safety is increasing, and a non-solvent adhesive that does not contain an organic solvent is desired.

  As the non-solvent type adhesive, a type of adhesive that develops an adhesive force when irradiated with ultraviolet rays, a so-called ultraviolet curable adhesive has been proposed. In addition to the fact that VOCs do not occur, UV curable adhesives do not require heating for the development of adhesive strength, can exhibit adhesive strength almost simultaneously with UV irradiation, and require a curing period for the production of adhesives. It has excellent properties not found in solvent-based pressure-sensitive adhesives, and its use is being expanded.

  For example, an ultraviolet curable pressure-sensitive adhesive composition containing a reactive polymer in which a compound having a double bond is introduced into the side chain of a (meth) acrylic polymer is disclosed (for example, Patent Document 1). reference).

JP 2001-64593 A

  The pressure-sensitive adhesive composition described in Patent Document 1 contains a (meth) acrylic acid ester monomer, a monofunctional monomer copolymerizable therewith, a photopolymerization initiator, and the like in addition to the reactive polymer. When the composition is irradiated with ultraviolet rays, the photopolymerization initiator acts, and a polymerization reaction proceeds between the reactive polymer and the (meth) acrylate monomer or monofunctional monomer, Adhesive strength is developed. And in patent document 1, according to this adhesive composition, compared with the conventional ultraviolet curing adhesive, coating suitability, adhesive force, heat-resistant holding force, and the adhesive reliability at the time of high temperature are improved. The effect is described.

  However, the pressure-sensitive adhesive composition described in Patent Document 1 still has a problem that durability when a glass material is used as an adherend, in particular, heat resistance and heat-and-moisture resistance are not yet satisfactory. However, there was still room for improvement.

  Thus, at present, a pressure-sensitive adhesive composition excellent in durability when using a glass material as an adherend, in particular, heat resistance and heat-and-moisture resistance has not yet been disclosed. Creation is eagerly desired by industry.

  The present invention has been made to solve the above-described problems of the prior art, and is a pressure-sensitive adhesive composition that is excellent in durability when a glass material is used as an adherend, in particular, heat resistance and moisture and heat resistance. Is to provide.

  As a result of intensive studies to solve the problems of the prior art as described above, the present inventors have found that as a reactive polymer, a (meth) acryloyl functional group and an alkoxy group are present in the side chain of the (meth) acrylic polymer. By using a modified (meth) acrylic polymer into which a silyl-based functional group has been introduced, the inventors have conceived that the above problems can be solved and completed the present invention. Specifically, the following ultraviolet curable pressure-sensitive adhesive composition is provided by the present invention.

[1] An ultraviolet curable pressure-sensitive adhesive composition containing, as essential components, a reactive polymer (component A) , a photopolymerization initiator (component B), and a monomer having a polymerizable double bond (component C). The A component contains a repeating unit derived from a (meth) acrylic monomer in the main chain and a functional group ((meth) acryloyl functional group) containing a (meth) acryloyl skeleton in the side chain . A modified (meth) acrylic polymer containing 3 to 40 mmol / 100 g and a functional group containing an alkoxysilyl skeleton (alkoxysilyl functional group) in an amount of 0.3 to 40 mmol / 100 g , and the modified (meth) acrylic polymer Has a weight average molecular weight (Mw) in the range of 50,000 to 1,000,000 and a glass transition temperature (Tg) in the range of 0 ° C to -55 ° C. When the total of the A component, the C-1 component, and the C-2 component is 100% by mass, including acrylate (C-1 component) and 4-hydroxybutyl acrylate (C-2 component), UV curable pressure-sensitive adhesive containing 2.5 to 30% by mass of the component A, 47.5 to 96.5% by mass of the C-1 component, and 1 to 50% by mass of the C-2 component. Composition.

  The ultraviolet curable pressure-sensitive adhesive composition of the present invention is excellent in durability when a glass material is used as an adherend, in particular, heat resistance and wet heat resistance.

  Hereinafter, the best mode for carrying out the ultraviolet curable pressure-sensitive adhesive composition of the present invention will be specifically described. However, the present invention includes all embodiments including the invention-specific matters, and is not limited to the embodiments described below.

[1] UV curable adhesive composition:
The ultraviolet curable pressure-sensitive adhesive composition of the present invention contains a reactive polymer (component A) , a photopolymerization initiator (component B), and a monomer having a polymerizable double bond (component C) as essential components. It is a curable pressure-sensitive adhesive composition. Hereinafter, each component will be described.

[1-A] Reactive polymer (component A):
In the composition of the present invention, as the component A, a functional group ((meth) acryloyl series) containing a repeating unit derived from a (meth) acrylic monomer in the main chain and a (meth) acryloyl skeleton in the side chain. A modified (meth) acrylic polymer having a functional group) and a functional group containing an alkoxysilyl skeleton (alkoxysilyl functional group) is used.

[1-A-1] Main chain:
The component A includes a repeating unit derived from a (meth) acrylic monomer in the main chain (hereinafter, “the repeating unit derived from the monomer X” may be simply referred to as “X unit”). In other words, the modified (meth) acrylic polymer of the present invention has a (meth) acrylic polymer as a basic skeleton. The reason why the (meth) acrylic monomer unit is contained in the main chain is that it makes it possible to exhibit excellent weather resistance and optical properties (translucency and transparency). In this specification, the term “main chain” means a carbon chain having the largest number of carbon atoms in the modified (meth) acrylic polymer.

  In general, “(meth) acrylic monomer” means acrylic acid, methacrylic acid, or derivatives thereof. Specifically, in addition to acrylic acid and methacrylic acid, methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, i-propyl (meth) acrylate, n-butyl (meth) acrylate, i -Butyl (meth) acrylate, t-butyl (meth) acrylate, n-pentyl (meth) acrylate, i-pentyl (meth) acrylate, n-hexyl (meth) acrylate, n-octyl (meth) acrylate, 2- (Meth) acrylic acid esters such as ethylhexyl (meth) acrylate, lauryl (meth) acrylate, cyclohexyl (meth) acrylate; 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxy Propyl (meth) acrylate, etc. Hydroxyl group-containing (meth) acrylates; (meth) acrylates such as ammonium (meth) acrylate, sodium (meth) acrylate, potassium (meth) acrylate; (meth) acrylamides such as (meth) acrylamide (Meth) acrylonitriles such as (meth) acrylonitrile;

  Among the (meth) acrylic monomers, the component A preferably includes a repeating unit derived from ethyl acrylate, butyl acrylate or 2-ethylhexyl acrylate, and further includes a repeating unit derived from ethyl acrylate or butyl acrylate. Those containing a repeating unit derived from ethyl acrylate are particularly preferred. This is because by including these repeating units, it is possible to exhibit good adhesiveness / adhesion performance.

  The component A may be a homopolymer whose main chain contains only one type of (meth) acrylic monomer unit, or a copolymer containing two or more types of (meth) acrylic monomer units. It may be a polymer. However, two or more types of (meth) acrylic monomers are used because it is easy to precisely adjust the physical properties of the coating film (sticky / adhesive layer) when used as a pressure-sensitive adhesive / adhesive. A copolymer containing units is preferred.

  In addition, as long as the A component contains a (meth) acrylic monomer unit, it is not necessary that all repeating units are (meth) acrylic monomer units. That is, as long as the effect of this invention is not inhibited, you may contain monomer units other than a (meth) acrylic-type monomer.

  Although there is no restriction | limiting in particular about the kind of "monomer other than (meth) acrylic-type monomer", For example, the monomer which has a polymerizable unsaturated bond can be used. Specifically, aromatic vinyls such as styrene and α-methylstyrene; vinyl carboxylates such as vinyl acetate and vinyl propionate; unsaturated dicarboxylic acids such as maleic anhydride, itaconic acid and fumaric acid; N-vinyl N-vinyl lactams such as pyrrolidone and N-vinylcaprolactam;

  In the (meth) acrylic monomer unit of component A, the content of the (meth) acrylic monomer unit is 100 masses of the total of monomer units constituting the main chain of the modified (meth) acrylic polymer. %, It is preferably 50% by mass or more, more preferably 90% by mass or more, and particularly preferably 100% by mass. That is, it is preferable that all of the main chain is composed of (meth) acryl monomer units. If the content of the (meth) acrylic monomer unit is less than 50% by mass, the viscosity / adhesion performance tends to decrease, such being undesirable.

[1-A-2] Side chain:
The component A has a functional group containing a (meth) acryloyl skeleton and a functional group containing an alkoxysilyl skeleton in the side chain. In other words, it can be said that a (meth) acryloyl functional group and an alkoxysilyl functional group are introduced and modified by chemical modification to the (meth) acrylic polymer serving as a basic skeleton. In the present specification, the term “side chain” means a carbon chain branched from the main chain (the carbon chain having the largest number of carbon atoms) of the modified (meth) acrylic polymer.

  Since the polymer having a (meth) acryloyl functional group (that is, a polymerizable functional group) in the side chain is cross-linked with each other by irradiation with ultraviolet rays, ultraviolet curability is exhibited. Moreover, in addition to high weather resistance, there is little adhesive residue on the adherend when the adhesive / adhesive is peeled off, and a preferable effect of hardly contaminating the adherend is exhibited. On the other hand, a polymer having an alkoxysilyl-based functional group in the side chain is excellent in durability when a glass material is used as an adherend, in particular, heat resistance and wet heat resistance. Specifically, it has excellent adhesiveness even under high temperature conditions or high temperature / high humidity conditions, and is characterized by high viscosity and adhesion performance.

  In this specification, the term “functional group containing (meth) acryloyl skeleton” means a functional group containing “acryloyl skeleton” or “methacryloyl skeleton” shown in Table 1 below, and constitutes an acryloyl skeleton or methacryloyl skeleton. It also includes substituted derivatives in which all or part of the hydrogen atoms to be substituted are substituted with other atoms or functional groups. In the present specification, these functional groups may be referred to as “(meth) acryloyl functional groups”.

  Typical examples include acryloyl group and methacryloyl group. An acryloyl group is preferred in that it can impart excellent polymerizability (and hence UV curable properties), and a methacryloyl group is preferred in terms of higher safety compared to an acryloyl group.

  In addition, the (meth) acryloyl functional group does not need to be a functional group having a structure in which the acryloyl skeleton or methacryloyl skeleton can be directly bonded to the main chain, and the acryloyl skeleton or methacryloyl skeleton is indirect via any atom or functional group. It may be a functional group having a structure that can be bonded to the main chain (for example, an acryloyloxy group).

The preferred content of the (meth) acryloyl functional group varies depending on the structure of the main chain, the weight average molecular weight, the glass transition temperature, the adhesive physical properties, etc., but is 0.3 to 40 mmol per 100 g of the modified (meth) acrylic polymer. It is necessary to be within the range, and it is particularly preferable to be within the range of 0.5 to 20 mmol. For example, if it is a modified (meth) acrylic polymer having a weight average molecular weight of about 300,000, it is preferable to have 0.33 to 330 (meth) acryloyl functional groups per molecule of the polymer, Those having 1.0 to 132 are more preferred, and those having 1.65 to 66 are particularly preferred.

When the content is less than 0.3 mmol / 100 g, a modification effect by a (meth) acryloyl functional group (specifically, effects such as ultraviolet curability, high weather resistance, and less adhesive residue on the adherend) ) Is not preferred because it may not be sufficiently obtained. On the other hand, if it exceeds 40 mmol / 100 g, it varies depending on the polymer composition and the like, but it tends to cause destabilization of the polymer, which is not preferable.

  In the present specification, the term “alkoxysilyl skeleton” means a skeleton in which at least one alkoxy group is bonded to a silicon atom, as shown in Table 1 above. Therefore, the “functional group containing an alkoxysilyl skeleton” includes a functional group in which a silicon atom is bonded to a functional group other than an alkoxy group in addition to an alkoxy group. In the present specification, these functional groups may be referred to as “alkoxysilyl functional groups”.

  Specific examples include trialkoxysilyl groups, dialkoxysilyl groups, monoalkoxysilyl groups, and the like. Among these, trialkoxysilyl groups are particularly preferable because they can be introduced using trialkoxysilane derivatives that are relatively easily available.

  The alkoxysilyl functional group does not need to be a functional group having a structure in which the alkoxysilyl skeleton can be directly bonded to the main chain, and the structure in which the alkoxysilyl skeleton can be indirectly bonded through any atom or functional group. (For example, a trialkoxysilylalkyl group).

The preferable content of the alkoxysilyl functional group varies depending on the structure of the main chain, the weight average molecular weight, the glass transition temperature, etc., but it is necessary to be within the range of 0.3 to 40 mmol per 100 g of the modified (meth) acrylic polymer. And is particularly preferably in the range of 0.5 to 20 mmol. For example, in the case of a modified (meth) acrylic polymer having a weight average molecular weight of 300,000, those having 0.33 to 330 alkoxysilyl functional groups per polymer molecule are preferable. Those having ˜132 are more preferred, and those having 1.65 to 66 are particularly preferred.

When the content is less than 0.3 mmol / 100 g, the modification effect by the alkoxysilyl-based functional group (specifically, durability when a glass material is used as an adherend, in particular, heat resistance and heat and humidity resistance) This is not preferable because there is a possibility that an effect such as excellent) may not be sufficiently obtained. On the other hand, if it exceeds 40 mmol / 100 g, it varies depending on the polymer composition and the like, but it tends to cause destabilization of the polymer, which is not preferable.

[1-A-3] Average molecular weight:
The A component needs to have a weight average molecular weight (Mw) in the range of 50,000 to 1,000,000. By setting the weight average molecular weight within this range, the miscibility with the diluent (monomer or solvent) becomes good and the composition can be easily prepared. A preferable effect is obtained that there is little adhesive residue on the substrate and it is difficult to contaminate the adherend.

  The component A preferably has a weight average molecular weight in the range of 100,000 to 700,000, particularly preferably in the range of 150,000 to 400,000. That is, those having a weight average molecular weight of around 300,000 are particularly preferred. When the weight average molecular weight is less than 50,000, the adhesive residue on the adherend tends to increase when the pressure-sensitive adhesive or adhesive is used, which is not preferable. On the other hand, if it exceeds 1,000,000, the miscibility with the diluent tends to be poor, such being undesirable.

  The weight average molecular weight is the polymerization conditions for polymerizing the (meth) acrylic polymer as the main chain, for example, the type and amount of the polymerization initiator, the type and amount of the chain transfer agent, the type and amount of the solvent, the reaction temperature. The reaction time can be adjusted within the above range by appropriately controlling the reaction time. Further, a commercially available (meth) acrylic polymer having a desired weight average molecular weight may be appropriately selected and subjected to modification.

  In this specification, “weight average molecular weight” means a weight average molecular weight in terms of polystyrene measured by GPC-LS method (Gel Permeation Chromatography-Light Scattering Method: GPC-light scattering method). .

[1-A-4] Glass transition temperature (Tg):
The component A needs to have a glass transition temperature (Tg) in the range of 0 ° C to -55 ° C. By setting the glass transition temperature within this range, an appropriate viscosity / adhesion performance is exhibited when a pressure-sensitive adhesive or adhesive is used.

The component A has a glass transition temperature in the range of −5 ° C. to −55 ° C. , more preferably in the range of −8 ° C. to −36 ° C. If the glass transition temperature exceeds 0 ° C., the adhesive / adhesive tends to decrease the viscosity and adhesive strength, which is not preferable. On the other hand, when the temperature is lower than −55 ° C., the adhesive residue on the adherend increases when used as a pressure-sensitive adhesive or an adhesive, and the adherend tends to be contaminated.

The glass transition temperature can be adjusted within the above range by appropriately controlling the type and ratio of the repeating units constituting the (meth) acrylic polymer serving as the main chain. The glass transition temperature (theoretical value) of the polymer P composed of repeating units derived from the monomers M ₁ , M ₂ ,... M _n can be calculated from Fox's formula (the following formula (1)). Therefore, what is necessary is just to adjust the kind and ratio of a repeating unit with reference to this formula.
1 / TgP = r ₁ / TgM ₁ + r ₂ / TgM ₂ ... + R _n / TgM _n (1)
(However, TgP: Glass transition temperature (K) of polymer P, TgM ₁ : Glass transition temperature (K) of homopolymer of monomer M ₁ , TgM ₂ : Glass of homopolymer of monomer M ₂ ) Transition temperature (K), TgM ₃ : Glass transition temperature (K) of homopolymer of monomer M _n , r ₁ : Mass fraction of monomer M ₁ unit in polymer P, r ₂ : Polymer P The mass fraction of the monomer M ₂ unit in, r _n : the mass fraction of the monomer M _n unit in the polymer P)

More specifically, since the modified (meth) acrylic polymer of the present invention has a relatively low glass transition temperature of 0 ° C. to −55 ° C., the glass transition temperature of the homopolymer is compared during the polymerization. A monomer mixture mainly composed of butyl acrylate (Tg: −55 ° C.), ethyl acrylate (Tg: −24 ° C.), 2-ethylhexyl acrylate (Tg: −85 ° C.), etc. A monomer having a relatively high glass transition temperature of a homopolymer, for example, methyl methacrylate (Tg: 105 ° C.), styrene (Tg: 100 ° C.) or the like is appropriately added to the polymerization reaction to obtain a desired glass. A polymer having a transition temperature can be obtained. Moreover, you may select suitably what has a desired glass transition temperature from commercially available (meth) acrylic-type polymers, and you may use this for modification | denaturation.

  In this specification, “glass transition temperature” means a glass transition temperature measured in accordance with JIS K7121 (plastic transition temperature measurement method).

[1-A-5] Production method:
Although the manufacturing method of A component is not specifically limited, For example, the method (chemical) which introduce | transduces (meth) acryloyl type functional group and alkoxysilyl type functional group by chemical modification with respect to the (meth) acrylic-type polymer used as a basic skeleton. (Modification method).

  Specific examples of the chemical modification method include, for example, a (meth) acrylic polymer having a hydroxyl group as a base polymer, and a (meth) acrylic compound having an isocyanate group or an alkoxysilane having an isocyanate group at the hydroxyl group of the base polymer. A method of introducing a (meth) acryloyl functional group and an alkoxysilyl functional group by directly bonding a system compound can be exemplified (direct bonding method).

  The “(meth) acrylic polymer having a hydroxyl group” is obtained by copolymerizing a hydroxyl group-containing (meth) acrylic acid ester such as 2-hydroxyethyl acrylate with another (meth) acrylic monomer. Can do. Examples of the “(meth) acrylic compound having an isocyanate group” include 2-methacryloyloxyethyl isocyanate (trade name: Karenz MOI, manufactured by Showa Denko KK) and 2-acryloyloxyethyl isocyanate (trade name: Karenz AOI, Showa). (Made by Denko Co., Ltd.). On the other hand, examples of the alkoxysilane compound having an isocyanate group include 3-isocyanatopropyltriethoxysilane.

  Further, as a chemical modification method, a polyfunctional compound such as a polyisocyanate compound is bonded to a hydroxyl group of a base polymer, and a (meth) acrylic compound having a hydroxyl group or an alkoxysilane having a hydroxyl group through the multifunctional compound. A method of introducing a (meth) acryloyl functional group and an alkoxysilyl functional group by indirectly bonding a system compound may be employed (indirect bonding method).

  Examples of the “polyisocyanate compound” include methylene diphenyl diisocyanate (MDI), tolylene diisocyanate (TDI), isophorone diisocyanate (IPDI), and the like. Examples of the “(meth) acrylic compound having a hydroxyl group” include the hydroxyl group-containing (meth) acrylic acid esters already described. Examples of the “alkoxysilane compound having a hydroxyl group” include 3-hydroxypropyltriethoxysilane.

  As the production method of the component A, the alkoxysilyl functional group is incorporated into the base polymer skeleton by copolymerizing a monomer having an alkoxysilyl functional group with another monomer, and a (meth) acryloyl type As for the functional group, a method of introducing the functional group by chemical modification to the base polymer can also be mentioned (polymerization method).

  The polymerization method will be described more specifically. A monomer mixture containing a (meth) acrylic monomer, a monomer having a hydroxyl group, and a monomer having an alkoxysilyl functional group is subjected to a polymerization reaction, and a side chain is obtained. A first modified (meth) acrylic polymer having the alkoxysilyl functional group and a hydroxyl group therein is obtained, and the first modified (meth) acrylic polymer is used as a base polymer. This is a method for obtaining a second modified (meth) acrylic polymer by introducing a (meth) acryloyl functional group by chemical modification.

  Examples of the “monomer having an alkoxysilyl-based functional group” include methacryloyloxytrialkoxysilane, acryloyloxytrialkoxysilane, and vinyltrialkoxysilane. Among these, methacryloyloxytrialkoxysilane or acryloyloxytrialkoxysilane is preferably used, and acryloyloxytrialkoxysilane is particularly preferably used in terms of high reactivity during polymerization.

The content of the A component varies depending on the structure of the polymer of the A component, the type of the B component, the type of adherend, the required adhesive properties, etc., but the total of the A component and the C component is 100% by mass. In this case, it is necessary to be in the range of 2.5 to 30% by mass, more preferably in the range of 15 to 25% by mass , and particularly preferably in the range of 10 to 20% by mass. . If the content is less than 2.5% by mass, the adhesive strength tends to decrease, such being undesirable. On the other hand, if it exceeds 30 parts by mass, the miscibility with these monomers tends to decrease when the C component or other monomer is used as the diluent, which is not preferable.

[1-B] Photopolymerization initiator (component B):
In the composition of the present invention, a photopolymerization initiator is used as the B component. The photopolymerization initiator means an additive having a catalytic action that, when added to a polymerization system, induces a polymerization reaction by light irradiation. In the present invention, the type is not particularly limited, and a conventionally known photopolymerization initiator can be used.

Examples of the component B include α-hydroxyacetophenone (trade name: Irgacure 184, manufactured by Ciba Specialty Chemicals ), α-aminoacetophenone, benzoin compounds, and acylphosphine oxide compounds (for example, Irgacure 819 (trade name). And photopolymerization initiators such as Ciba Specialty Chemicals , Lucirin TPO (trade name, manufactured by BASF), etc. Among them, α-hydroxyacetophenone, α-aminoacetophenone and acyl are preferred because of their high reactivity. Phosphine oxide compounds are preferable, and α-hydroxyacetophenone and acyl phosphine oxide compounds are particularly preferable.

The preferred content of the B component varies depending on the structure of the polymer of the A component, the type of the B component, the type of adherend, the required adhesive properties, etc., but the A component , the C-1 component and the C- When the total of the two components is 100 parts by mass, it is preferably in the range of 0.5 to 10 parts by mass, more preferably in the range of 1 to 5 parts by mass, and 2 to 4 parts by mass. It is particularly preferable that it is within the range. If the content is less than 0.5 parts by mass, the action as a photopolymerization initiator may not be sufficiently exhibited, which is not preferable. On the other hand, if it exceeds 10 parts by mass, the performance as a pressure-sensitive adhesive tends to decrease due to the remaining B component, which is not preferable.

[1-C] Monomer having polymerizable double bond (C component):
The compositions of the present invention, in addition to the A and B components, comprising as constituent monomer (C component) having a polymerizable double bond. By containing C component, while the adhesiveness with respect to a to-be-adhered body and durability at the time of use improve, the preferable effect that application of an adhesive composition becomes easy is exhibited.

  The type of C component is not particularly limited as long as it is a monomer having a polymerizable double bond such as a vinyl group. Therefore, what is necessary is just to select suitably according to the required performance (adhesive force, transparency, a color, etc.) as an adhesive composition.

However, since the composition of the present invention is a non-solvent type pressure-sensitive adhesive composition, the component C is preferably a liquid and low-viscosity monomer. Moreover, since the composition of this invention is an ultraviolet curable adhesive composition, it is preferable to use the monomer used for ultraviolet polymerization. Examples of the monomer having a polymerizable double bond include, in addition to acrylic acid and methacrylic acid, methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, and i-propyl (meth) acrylate. , N-butyl (meth) acrylate, i-butyl (meth) acrylate, t-butyl (meth) acrylate, n-pentyl (meth) acrylate, i-pentyl (meth) acrylate, n-hexyl (meth) acrylate, (Meth) acrylic acid esters such as n-octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, cyclohexyl (meth) acrylate; 2-hydroxyethyl (meth) acrylate, 2- Hydroxypropyl (meth) acrylate, 3-hydro Hydroxyl-containing (meth) acrylic acid esters such as cypropyl (meth) acrylate; 1,6-hexanediol diacrylate, 1,9-nonanediol diacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol pentaacrylate And polyfunctional acrylates such as dipentaerythritol hexaacrylate; vinyl carboxylates such as vinyl acetate and vinyl propionate; aromatic vinyls such as styrene and α-methylstyrene;

Among these, the composition of the present invention contains tetrahydrofurfuryl acrylate (C-1 component) and 4-hydroxybutyl acrylate (C-2 component) as essential components as the C component. When C-1 component is contained, the preferable effect that viscosity falls and coatability improves and the adhesiveness with respect to a to-be-adhered body improves is exhibited. On the other hand, when the C-2 component is contained, a preferable effect of improving durability during use is exhibited.

  The preferred content of component C depends on the structure of the polymer of component A, the type of component B, the type of adherend, the required adhesive properties, etc., but the total of component A and component C is 100% by mass. In this case, it is preferably in the range of 70 to 97.5% by mass, more preferably in the range of 75 to 95% by mass, and particularly preferably in the range of 80 to 90% by mass. If the content is less than 70% by mass, the miscibility with component A tends to decrease, such being undesirable. On the other hand, if it exceeds 97.5 parts by mass, there is a tendency to cause a problem that the adhesive strength is lowered, which is not preferable.

The content of the C-1 component needs to be in the range of 47.5 to 96.5% by mass, where the total of the A component , the C-1 component, and the C-2 component is 100% by mass. There, more preferably in the range of 55 to 90% by weight, particularly preferably in the range of 60 to 80 wt%. If the content is less than 47.5% by mass, the miscibility with the component A tends to decrease, such being undesirable. On the other hand, if it exceeds 96.5 parts by mass, there is a tendency to cause a problem that the adhesive strength is lowered, which is not preferable.

The content of the C-2 component needs to be in the range of 1 to 50% by mass when the total of the A component , the C-1 component, and the C-2 component is 100% by mass. More preferably, it is in the range of 5 to 30% by mass, and particularly preferably in the range of 5 to 20% by mass. When the content is less than 1% by mass, an adhesive residue is generated when the adherend (glass material) is peeled off, and the adherend tends to be contaminated. On the other hand, if it exceeds 50 parts by mass, it tends to cause a problem that the adhesive strength is lowered, which is not preferable.

[1-D] UV absorber:
You may mix | blend a ultraviolet absorber with the composition of this invention in addition to the said structural component. By blending UV absorbers, UV rays with strong chemical action are shielded, oxidation and alteration of substances existing on the lower layer side than the adhesive layer, or degradation due to decomposition of organic substances (discoloration, fading, embrittlement, etc.) ) Is preferably exhibited (hereinafter sometimes referred to as “ultraviolet ray shielding”).

  Examples of UV absorbers include organic UV absorbers such as benzophenone compounds and benzotriazole compounds, salicylic acid esters, triazine compounds, and cyanoacrylate compounds; inorganic UV absorbers such as zinc oxide and titanium oxide Agents; and the like.

  However, in the composition of the present invention, the absorption spectrum patterns of the B component and the ultraviolet absorber are matched in order to impart ultraviolet shielding properties without inhibiting the action of the photopolymerization initiator (B component). Preferably not. In the composition of the present invention, it is preferable to use a component having an absorption wavelength region in the range of 200 to 440 nm as the B component and a component having an absorption wavelength region in the range of 200 to 415 nm as the ultraviolet absorber. Specifically, it is preferable to use a UV absorber whose λmax is in a wavelength region different from λmax of the B component. For example, when a component having λmax within the range of 240 to 250 nm is used as the B component, an ultraviolet absorber having λmax within the range of 280 to 300 nm is preferably used, and the component B is within the range of 280 to 300 nm. In the case of using those having λmax, it is preferable to use an ultraviolet absorber having λmax within the range of 310 to 330 nm, and when using those having λmax within the range of 380 to 410 nm as the B component, It is preferable to use an ultraviolet absorber having λmax in the range of 340 to 380 nm.

Examples of the photopolymerization initiator having an absorption wavelength region in the range of 200 to 440 nm include α-hydroxyacetophenone (trade name: Irgacure 184, manufactured by Ciba Specialty Chemicals ), α-aminoacetophenone, benzoin compounds, and the like. Examples include acylphosphine oxide compounds (for example, Irgacure 819 (trade name, manufactured by Ciba Specialty Chemicals ), Lucirin TPO (trade name, manufactured by BASF)), and the like. On the other hand, as an ultraviolet absorber having an absorption wavelength region in the range of 200 to 415 nm (that is, an ultraviolet absorber having λmax in the wavelength region of 280 to 380 nm), for example, 2,2 ′, 4,4′-tetra Hydroxybenzophenone (trade name: DAINSORB P-6, manufactured by Daiwa Kasei Co., Ltd.), 2,2′-dihydroxy-4,4′-dimethoxybenzophenone (trade name: SEESORB107, manufactured by Cypro Kasei Co., Ltd.), 2- (3-di- t-butyl-2-hydroxy-5-methylphenyl) -5-cyclo-2H-benzotriazole (trade name: Tinuvin 326, manufactured by Ciba Specialty Chemicals ), 2,4-dihydroxybenzophenone (trade name: SEESORB100, Cypro) (Made by Kasei Co., Ltd.). Therefore, in the composition of the present invention, it is preferable to use a combination of the photopolymerization initiator and the ultraviolet absorber.

[1-E] Other additives:
In addition to the above components, the composition of the present invention includes tackifiers, anti-aging agents, colorants, light stabilizers, coupling agents, thermal polymerization inhibitors, leveling agents, surfactants, storage stabilizers, You may mix | blend additives which may be mix | blended with adhesive compositions, such as a plasticizer and a filler.

  Examples of the tackifier include rosin (trade name: Neotol 101K, manufactured by Harima Chemicals), hydrogenated rosin (trade name: Pine Crystal KE-100, manufactured by Arakawa Chemical Co., Ltd.), ester gum, polyterpene resin (trade name). : Clearon P125, manufactured by Yasuhara Chemical Co., Ltd.), polyolefin resin, polystyrene resin, aromatic petroleum resin (trade name: Alcon SM-10, manufactured by Arakawa Chemical Co., Ltd.), alicyclic hydrogenated petroleum resin, etc. it can.

Antiaging agents include, for example, Irganox series (trade name, manufactured by Ciba Specialty Chemicals ) 245, 259, 565, 1010, 1035, 1076, 1081, 1098, 1222, and 1330 (both trade names, Ciba Specialty chemicals ).

As the light stabilizer, for example, Tinuvin series (trade name, manufactured by Ciba Specialty Chemicals ) 292, 144, 622LD, Sanol series (trade name, manufactured by Sankyo Co., Ltd.) LS770, LS440, Sumisorb TM-061 ( Trade name, manufactured by Sumitomo Chemical Co., Ltd.).

Examples of the coupling agent include γ-aminopropyltrimethoxysilane, γ-mercaptopropyltriethoxysilane, γ-methacryloxypropyltriethoxysilane, and the like. Commercially available coupling agents include SH series (trade name, manufactured by Toray Dow Corning Silicone) 6020, 6020P, 6062, 6030, KBE series (trade name, manufactured by Shin-Etsu Chemical Co., Ltd.) 903, 603, 403, etc. Can be mentioned.

[2] Manufacturing method:
The composition of the present invention is obtained by mixing the A component , B component, C-1 component and C-2 component , which are essential components, and UV absorbers and other additives, which are optional constituent components, at a predetermined ratio. be able to.

[3] How to use:
The composition of the present invention can be used for coating as it is without dissolving in the organic solvent. For example, what is necessary is just to form a coating film by apply | coating to the surface of a to-be-adhered body with conventionally well-known coating apparatuses, such as an applicator, and drying.

  Examples of the adherend to which the composition of the present invention can be applied include polyethylene, polypropylene, polyvinyl chloride, polyethylene terephthalate, polycarbonate, polysulfone, polymethyl methacrylate, polystyrene, polybutadiene, ABS resin, AS resin, AES resin, nylon, Examples include thermoplastic resins such as cellulose, nitrocellulose, and triacetyl cellulose; thermosetting resins such as phenol formaldehyde resin, cresol formaldehyde resin, melamine resin, and urea resin; inorganic materials such as glass, ceramics, and metals; .

  The composition of the present invention develops adhesive strength when irradiated with ultraviolet rays. Although there is no restriction | limiting in particular about the wavelength of an ultraviolet-ray, It is preferable to irradiate an ultraviolet-ray with a wavelength of 200-400 nm. Specific examples of the light source include an ultrahigh pressure mercury lamp, a high pressure mercury lamp, a metal halide lamp, and a high power metal halide lamp.

  Hereinafter, the ultraviolet curable pressure-sensitive adhesive composition of the present invention will be described more specifically with reference to examples. However, these examples merely show some embodiments of the present invention. Accordingly, the present invention should not be construed as being limited to these examples.

[Synthesis of component A]
First, a modified (meth) acrylic polymer of component A was synthesized.

(Reference Comparative Example 1)
A commercially available acrylic copolymer (trade name: Paraclone AW4500H, solid content 40%, toluene solvent, manufactured by Negami Kogyo Co., Ltd.) was used as the polymer of Reference Comparative Example 1.

(Reference Example 1)
In a four-necked flask (2 L) equipped with a condenser, a dropping funnel and a thermometer, 586 g of a commercially available acrylic copolymer (trade name: Paracron AW4500H, solid content 40%, toluene solvent, manufactured by Negami Kogyo Co., Ltd.), solvent 890 g of (ethyl acetate) and 0.3 g of a reaction catalyst (dibutyltin laurate) were charged and heated to 40 ° C. with stirring. This acrylic copolymer contains butyl acrylate units, ethyl acrylate units, methyl methacrylate units, hydroxybutyl acrylate units and hydroxyethyl acrylate units, and has a weight average molecular weight of about 330,000 and a glass transition temperature of −8 ° C. Met. Moreover, the hydroxyl group content of this acrylic copolymer was 15 mmol per 100 g of acrylic copolymer (50 per molecule of copolymer).

1.8 g of (meth) acrylic compound (2-methacryloyloxyethyl isocyanate, trade name: Karenz MOI, Showa Denko KK) and alkoxysilane compound (3-isocyanatepropyltriethoxysilane, commercial product) prepared in advance Name: KBE-9007, manufactured by Shin - Etsu Chemical Co., Ltd.) A solution prepared by dissolving 1.1 g in 120 g of solvent (ethyl acetate) was dropped into the four-necked flask through the dropping funnel. This dropping was performed over about 1 hour while maintaining the temperature inside the four-necked flask at 40 ° C.

  The reaction was continued at a temperature of 40 ° C. even after completion of the dropwise addition, and when the disappearance of the isocyanate group was confirmed by titration analysis of the reaction solution, the reaction was terminated and a modified (meth) acrylic polymer was obtained. The reaction time was 5 hours from the start of the dropwise addition of the mixed solution. The results are shown in Table 2.

(Reference Examples 2-12)
A modified (meth) acrylic polymer was obtained in the same manner as in Reference Example 1 except that the conditions such as the type of base polymer, the modification rate of the methacryloyl group, the modification rate of the triethoxysilyl group were changed (A- 2 to A-12 component). The results are shown in Table 2.

[IR]
The resulting polymer was analyzed by infrared spectroscopy (IR). 1 is an IR chart of a commercially available acrylic copolymer of Reference Comparative Example 1. FIG. FIG. 2 is an IR chart of the polymer obtained in Reference Example 1.

When comparing the IR chart of the polymer obtained in Reference Example 1 and the polymer of Reference Comparative Example 1, the polymer obtained in Reference Example 1 is an isocyanate derived from a (meth) acrylic compound or an alkoxysilane compound. absent peak (2273~2000 / cm ^-1) is showing a group, peaks indicating the presence of a secondary amide of the urethane bond to the base polymer was not present (1570~1510 / cm ^-1, 866~800 / Cm ⁻¹ ) and peaks indicating the presence of triethoxysilyl groups (1110 / cm ⁻¹ , around 950 / cm ⁻¹ ) appear. From this, it was recognized that the polymer obtained in Reference Example 1 had both a methacryloyl group and a triethoxysilyl group. The polymers obtained in Reference Examples 2 and 4 to 12 showed the same results as the polymer of Reference Example 1. However, in the polymer of Reference Example 3, no peak indicating the presence of a triethoxysilyl group was observed.

[Weight average molecular weight]
The weight average molecular weight in terms of polystyrene of the polymer obtained in Reference Example 1 was measured by the GPC-LS method. As a result, the weight average molecular weight was 335,000 and was in the range of 50,000 to 1,000,000. Moreover, since low molecular weight components having a molecular weight of 1,000 or less are not detected except for low molecular weight components derived from raw materials, free (meth) acrylic compounds, alkoxysilane compounds, or low molecular weight compounds derived therefrom are used. Was not considered to exist. That is, it was recognized that (meth) acrylic compounds and alkoxysilane compounds all reacted with the base polymer, and (meth) acryloyl groups and trialkoxysilyl groups were reliably introduced. The polymers obtained in Reference Examples 2 to 9, 11 to 12 had a weight average molecular weight in the range of 50,000 to 1,000,000 and showed the same results as the polymer of Reference Example 1. However, the polymer of Reference Example 10 had a weight average molecular weight of 11,000 and was outside the range of 50,000 to 1,000,000.

[Glass-transition temperature]
The glass transition temperature of the polymer obtained in Reference Example 1 was measured according to JIS K7121 (plastic transition temperature measurement method). As a result, the glass transition temperature was −8 ° C., which was in the range of 0 ° C. to −55 ° C. The polymers obtained in Reference Examples 2 to 11 had a glass transition temperature in the range of 0 ° C. to −55 ° C., and showed the same results as the polymer of Reference Example 1. However, the polymer of Reference Example 12 had a glass transition temperature of 7 ° C. and was outside the range of 0 ° C. to −55 ° C.

[Methacryloyl group content / triethoxysilyl group content]
Furthermore, the methacryloyl group content and triethoxysilyl group content of the polymer obtained in Reference Example 1 were quantified by acid-base titration method. Specifically, the obtained polymer is mixed with di-n-butylamine (DBA), unreacted isocyanate groups of (meth) acrylic compounds and alkoxysilane compounds are reacted with DBA, and the consumed DBA The amount was quantified by back titration with hydrochloric acid. As a result, DBA was not consumed, and it was considered that the total amount of the (meth) acrylic compound and alkoxysilane compound reacted with the base polymer. When converted to the functional group content, the methacryloyl group content was 3 mmol / 100 g (10 per polymer molecule), and the triethoxysilyl group content was 3 mmol / 100 g (10 per polymer molecule). The methacryloyl group content and triethoxysilyl group content of the polymers obtained in Examples 2 to 12 were values as shown in Table 2, respectively.

[Preparation of pressure-sensitive adhesive composition]
The ultraviolet curable adhesive composition was prepared using the A component (A-1 to A-12 component) synthesized in Reference Examples 1 to 12.

Example 1
10 parts by mass of the modified (meth) acrylic polymer (component A-1) synthesized in Reference Example 1, 3 parts by mass of a photopolymerization initiator (component B), 80 parts by mass of tetrahydrofurfuryl acrylate (component C-1) and 10 parts by mass of 4-hydroxybutyl acrylate (component C-2) was mixed to prepare an ultraviolet curable pressure-sensitive adhesive composition.

(Examples 2-9, Comparative Examples 1-4)
An ultraviolet curable pressure-sensitive adhesive composition was prepared in the same manner as in Example 1 except that the type and amount of the A component, and the amounts of the B component, the C-1 component, and the C-2 component were changed. The composition is shown in Table 3.

[Adhesiveness]
The tackiness of the obtained pressure-sensitive adhesive composition was evaluated by the following method and criteria. Specifically, 50 g of the composition to be evaluated is used as it is as a coating liquid, and this coating liquid is applied to the surface of the PET film with an applicator, dried, and then irradiated with ultraviolet light having a wavelength of 200 to 400 nm with an ultrahigh pressure mercury lamp. By curing with ultraviolet rays, a coating film (adhesive layer) having a thickness of 25 μm was formed on the surface of the PET film. Thereafter, the PET film having the pressure-sensitive adhesive layer was bonded to alkali glass (trade name: general hard glass) to form a laminate. This laminate is exposed in a normal state (temperature: 25 ° C., humidity: 50%) for 1000 hours, and the adhesive strength between the PET film and the alkali glass after that is described in JIS Z0237 (adhesive tape / adhesive sheet test method). Measured by peel test. Further, the adhesive residue on the surface of the alkali glass at this time was visually evaluated.

  “◎” (very good) for those with an adhesive strength of 10 N / 25 mm or more “Good” for those with 5 N / 25 mm or more and less than 10 N / 25 mm, “×” (bad) for those with less than 5 N / 25 mm It was. Regarding the adhesive residue, the case where no adhesive residue was visually recognized was evaluated as “◯” (good), and the case where even a slight adhesive residue was observed visually was determined as “x” (defective). The results are shown in Table 3.

  The composition obtained in Example 1 showed good results in both adhesive strength and adhesive residue. The compositions obtained in Examples 2 to 9 also showed the same results as the composition obtained in Example 1. When the same test was conducted with the compositions of Comparative Examples 1 to 4, the compositions of Comparative Examples 1 and 3 to 4 were inferior in adhesive strength. Moreover, the adhesive residue of 50 area% was recognized by the composition of the comparative example 3 with respect to the total coating-film area of an adhesive layer. That is, the adhesive residue was also poor.

[Heat-resistant]
The heat resistance of the obtained pressure-sensitive adhesive composition was evaluated by the following method and criteria. Specifically, 50 g of the composition to be evaluated is used as it is as a coating solution, this coating solution is applied to the surface of the PET film with an applicator, dried, and then irradiated with ultraviolet light having a wavelength of 200 to 400 nm with an ultrahigh pressure mercury lamp. By curing with ultraviolet rays, a coating film (adhesive layer) having a thickness of 25 μm was formed on the surface of the PET film. Thereafter, the PET film having the pressure-sensitive adhesive layer was bonded to alkali glass (trade name: general hard glass) to form a laminate. This laminate is exposed for 1000 hours under each condition of high temperature (80 ° C.), and the adhesive strength between the PET film and the alkali glass after that is 180 ° peel according to JIS Z0237 (adhesive tape / adhesive sheet test method). It was measured in a test. Further, the adhesive residue on the surface of the alkali glass at this time was visually evaluated.

The adhesive force ratio R ₁ calculated by the following formula (2) from the adhesive force T ₁ after being exposed in the normal state in the evaluation of the adhesive property and the adhesive force T ₂ after being exposed under a high temperature condition is 70 to 150. % Was evaluated as “◯” (good), and the case where the adhesive strength ratio R ₁ was out of the range of 70 to 150% was evaluated as “x” (defect). Regarding the adhesive residue, the case where no adhesive residue was visually recognized was evaluated as “◯” (good), and the case where the adhesive residue was visually observed was evaluated as “x” (bad). The results are shown in Table 3.
R ₁ = (T ₂ / T ₁ ) × 100 (2)
(However, T ₁ : Adhesive strength after exposure under normal conditions (N / 25 mm), T ₂ : Adhesive strength after exposure under high temperature conditions (N / 25 mm), R ₁ : Adhesive strength ratio (%))

  The composition obtained in Example 1 shows little change in the adhesive strength of the pressure-sensitive adhesive layer even after being exposed for a long time under high temperature conditions, and no adhesive residue on the surface of the alkali glass is observed. Showed sex. The compositions obtained in Examples 2 to 9 also showed the same results as the composition obtained in Example 1. When the same test was carried out with the compositions of Comparative Examples 1 to 4, it was found that the adhesive strength after the composition of Comparative Example 3 was exposed under high temperature conditions varied significantly. That is, the composition of Comparative Example 3 had poor heat resistance.

[Moisture and heat resistance]
The heat resistance of the obtained pressure-sensitive adhesive composition was evaluated by the following method and criteria. Specifically, 50 g of the composition to be evaluated is used as it is as a coating solution, this coating solution is applied to the surface of the PET film with an applicator, dried, and then irradiated with ultraviolet light having a wavelength of 200 to 400 nm with an ultrahigh pressure mercury lamp. By curing with ultraviolet rays, a coating film (adhesive layer) having a thickness of 25 μm was formed on the surface of the PET film. Thereafter, the PET film having the pressure-sensitive adhesive layer was bonded to alkali glass (trade name: general hard glass) to form a laminate. This laminate is exposed for 1000 hours under conditions of high temperature and high humidity (temperature: 60 ° C., humidity: 90%), and the adhesive strength between the PET film and alkali glass is measured according to JIS Z0237 (adhesive tape / adhesive). Measurement was performed by the 180 ° peel test described in the sheet test method).

The adhesive strength ratio R ₂ calculated from the following formula (3) from the adhesive strength T ₁ after exposure under normal conditions in the evaluation of the adhesive property and the adhesive strength T ₃ after exposure under high temperature / high humidity conditions is The case where it was in the range of 70 to 150% was evaluated as “◯” (good), and the case where the adhesive strength ratio R ₂ was out of the range of 70 to 150% was evaluated as “x” (defect). Regarding the adhesive residue, the case where no adhesive residue was visually recognized was evaluated as “◯” (good), and the case where the adhesive residue was visually observed was evaluated as “x” (bad). The results are shown in Table 3.
R ₂ = (T ₃ / T ₁ ) × 100 (3)
(However, T ₁ : Adhesive strength after exposure under normal conditions (N / 25 mm), T ₃ : Adhesive strength after exposure under high temperature and high humidity conditions (N / 25 mm), T ₂ (N / 25 mm), R ₂ : Adhesive strength ratio (%))

  The composition obtained in Example 1 shows little variation in the adhesive strength of the pressure-sensitive adhesive layer even after being exposed for a long time under high temperature and high humidity conditions, and no adhesive residue on the alkali glass surface is observed. Good heat and humidity resistance was exhibited. The compositions obtained in Examples 2 to 9 also showed the same results as the composition obtained in Example 1. When the same test was carried out with the compositions of Comparative Examples 1 to 4, it was found that the adhesive strength after exposure of all the compositions of Comparative Examples 1 to 4 under high temperature and high humidity conditions was significantly reduced. It was. That is, the compositions of Comparative Examples 1 to 4 had poor moisture and heat resistance. In particular, the composition of Comparative Example 3 was 100% by area with respect to the total coating area of the pressure-sensitive adhesive layer, that is, adhesive residue was observed in all portions of the pressure-sensitive adhesive layer. That is, the composition of Comparative Example 3 was extremely poor in heat and moisture resistance.

[Color difference]
The color difference of the obtained adhesive composition was evaluated by the following methods and criteria. Specifically, 50 g of the composition to be evaluated is used as it is as a coating solution, this coating solution is applied to the surface of the PET film with an applicator, dried, and then irradiated with ultraviolet light having a wavelength of 200 to 400 nm with an ultrahigh pressure mercury lamp. By curing with ultraviolet rays, a coating film (adhesive layer) having a thickness of 25 μm was formed on the surface of the PET film. Thereafter, the PET film having the pressure-sensitive adhesive layer was bonded to alkali glass (trade name: general hard glass) to form a laminate. The color difference (b *) at 25 ° C. of this laminate was measured with a color difference meter (trade name: SpectroPhotometer SQ-2000, manufactured by Nippon Denshoku Industries Co., Ltd.). Moreover, the color difference was measured by the same method also about the laminated body after a heat resistance test, and the laminated body after a heat-and-moisture resistance test. A color difference (b *) of 1.5 or less was evaluated as good, and a color difference (over 1.5) was evaluated as poor. The results are shown in Table 3. As shown in Table 3, with respect to the color difference, both the compositions of Examples 1 to 9 and the compositions of Comparative Examples 1 to 4 showed good results.

[Haze]
The haze of the obtained pressure-sensitive adhesive composition was evaluated by the following method and criteria. Specifically, 50 g of the composition to be evaluated is used as it is as a coating solution, this coating solution is applied to the surface of the PET film with an applicator, dried, and then irradiated with ultraviolet light having a wavelength of 200 to 400 nm with an ultrahigh pressure mercury lamp. By curing with ultraviolet rays, a coating film (adhesive layer) having a thickness of 25 μm was formed on the surface of the PET film. Thereafter, the PET film having the pressure-sensitive adhesive layer was bonded to alkali glass (trade name: general hard glass) to form a laminate. The haze at 25 ° C. of this laminate was measured with a turbidimeter (trade name: HAZEMETER HM-150, manufactured by Murakami Color Research Laboratory). Moreover, the haze was measured by the same method also about the laminated body after a heat resistance test, and the laminated body after a heat-and-moisture resistance test. A haze of 2.0 or less was evaluated as good, and a haze exceeding 2.0 was evaluated as defective. The results are shown in Table 3. As shown in Table 3, with respect to haze, both the compositions of Examples 1 to 9 and the compositions of Comparative Examples 1 to 4 showed good results.

  Since the ultraviolet curable pressure-sensitive adhesive composition of the present invention is excellent in durability when a glass material is used as an adherend, in particular, heat resistance and heat and moisture resistance, the adherend is a glass material. It can be suitably used as a pressure-sensitive adhesive that requires heat, for example, a pressure-sensitive adhesive for optical equipment such as a display.

  In addition, the ultraviolet curable pressure-sensitive adhesive composition of the present invention is made of a material other than glass, for example, a polar resin material (PET, etc.) or a nonpolar resin material (PE, PP, etc.) provided with polarity by corona discharge treatment or the like. ) Also exhibits good adhesiveness, and therefore can be suitably used for applications such as bonding glass materials and these resin materials.

4 is an IR chart of the polymer of Reference Comparative Example 1. 3 is an IR chart of the polymer obtained in Reference Example 1.

Claims (1)

An ultraviolet curable pressure-sensitive adhesive composition containing a reactive polymer (component A) , a photopolymerization initiator (component B) and a monomer having a polymerizable double bond (component C) as essential components,
Wherein component A, in the main chain include (meth) repeating units derived from acrylic monomers in the side chain (meth) functional group containing acryloyl backbone ((meth) acryloyl functional group) 0.3 A modified (meth) acrylic polymer containing 0.3 to 40 mmol / 100 g of a functional group (alkoxysilyl functional group) containing ˜40 mmol / 100 g and an alkoxysilyl skeleton ,
The modified (meth) acrylic polymer has a weight average molecular weight (Mw) in the range of 50,000 to 1,000,000 and a glass transition temperature (Tg) in the range of 0 ° C. to −55 ° C.,
As said C component, tetrahydrofurfuryl acrylate (C-1 component) and 4-hydroxybutyl acrylate (C-2 component) are contained,
When the total of the A component, the C-1 component, and the C-2 component is 100% by mass, the A component is 2.5-30% by mass, and the C-1 component is 47.5-96. An ultraviolet curable pressure-sensitive adhesive composition containing 5% by mass and the C-2 component in a range of 1 to 50% by mass .

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