JP2019147916A - Adhesive sheet, article and manufacturing method of article - Google Patents

Abstract

To provide an adhesive sheet suppressing swelling or floating of a laminate member, generated due to out gas from a molded article surface or residual stress of the laminate member or the like, and capable of being adhered to an adherend having a surface through which no active energy ray transmits, and a molded article by laminating the sheet.SOLUTION: An adhesive sheet is used for an application for adhering two or more adherends having a surface through which no active energy ray transmits, and has storage elastic modulus of an adhesive layer at 25°C before irradiation of an adhesive layer surface with an active energy ray of 1×10to 1×10Pa, storage elastic modulus of the adhesive layer at 25°C after irradiation of an adhesive layer surface with an active energy ray of 1×10to 1×10Pa, and storage elastic modulus of an adhesive layer at 100°C after a curing reaction of 2×10Pa or more.SELECTED DRAWING: None

Description

  The present invention relates to an adhesive sheet, an article to which the adhesive sheet is attached, and a method for manufacturing the article.

  Resin molded products used for the exterior of home appliances, the exterior of mobile terminals, the interior and exterior of automobiles, etc., are parts molded in a three-dimensional direction by injection molding or extrusion molding. On these molded product surfaces, a hard coat layer, a mat layer, etc. are laminated by direct application to the molded product surface for the purpose of preventing scratches, or a hard coat layer, a mat layer, etc. are laminated on the surface. The joint member is laminated by a method in which resins are welded together when a molded product is molded by an injection in-mold molding machine, a method in which a liquid adhesive or the like is applied to the back surface of the pasting member, and is pasted. In recent years, in terms of appearance quality such as smoothness of the hard coat layer surface and uniformity of layer thickness, and for small lot production, the hard coat layer and mat layer are not directly laminated on the molded product, There are many methods of bonding a bonding member having a hard coat layer laminated on the surface in advance to the surface of the molded product (for example, Patent Document 1). In addition, in the welding of resins with an injection in-mold molding machine, since air bubbles easily accumulate in the gap between the bonding member and the molded product, the adhesive is laminated by applying a liquid adhesive or the like to the back surface of the bonding member. There are many cases. In this case, the bonding member is applied to the surface of one side and then heated to about 100 to 160 ° C. using a vacuum / pressure air bonding machine or the like, and then the molded product is pressed against the bonding member. There is a case in which a method of bonding to the surface of the molded product is taken with the stretching of the bonding member.

  In the method of applying a liquid adhesive that undergoes a curing reaction with heat or moisture on the back surface of the pasting member, a curing time of about 24 hours is required from the pasting of the liquid adhesive to the completion of curing. In addition, there is a problem that the bonding member is floated or peeled off during curing, or the liquid adhesive flows and the layer thickness is easily changed when the bonding member is stretched by the molding machine.

  Also, in the case of an adhesive or adhesive sheet that undergoes a curing reaction due to heat, the molded product to be affixed is a material with poor heat resistance such as polycarbonate, polymethylmethacrylate, acrylonitrile-butadiene-styrene, etc. In some cases, it is difficult to be cured at a temperature exceeding that. In addition, in the case of an adhesive or adhesive sheet that undergoes a curing reaction at a temperature of about 100 ° C. or less, the storage stability is extremely poor, and refrigeration storage or freezing storage is necessary.

  In addition, when an ultraviolet curing reaction type adhesive or an adhesive sheet (for example, Patent Document 2) is used, ultraviolet rays reach the adhesive layer by a decorative printing layer or the like printed on the front or back surface of the bonding member. When there are difficult portions or when a light-resistant resin transparent sheet is used, there is a problem that ultraviolet rays cannot be transmitted, so that ultraviolet rays cannot be cured.

  Moreover, when bonding a bonding member with a thermoplastic pressure-sensitive adhesive tape, the elastic modulus of the pressure-sensitive adhesive does not change while being low, and when bonding to the surface of a molded product with heat stretching of the bonding member, Then, when left in a humid heat environment for the reliability evaluation of the molded product, swelling or floating occurs due to outgas from the bonding member or the molded product, or residual when the bonding member is stretched There was a problem that swelling and floating were likely to occur due to stress. Moreover, in order to suppress outgas generation | occurrence | production from a bonding member or a molded article, the process of heating these members beforehand and releasing gas was needed, and it was inferior to production efficiency (for example, patent document 3). .

JP 2014-0925580 A Japanese Patent Laying-Open No. 2015-072343 JP 2014-205335 A

  The problem to be solved by the present invention is to suppress the swelling and floating of the bonding member, which is caused by outgas from the surface of the molded product or the residual stress of the bonding member, and the surface through which the active energy ray does not pass. The present invention provides an adhesive sheet that can be attached even to an adherend that has an adhesive, and a bonded molded product.

The present inventor has found that the above problems can be solved by an adhesive sheet having adhesive layers having various tensile elastic moduli.
That is, this invention is an adhesive sheet used for the use which bonds the 2 or more to-be-adhered body which has the surface which an active energy ray does not permeate | transmit, and is 25 degreeC before irradiating an active energy ray to the adhesive bond layer surface. The tensile storage elastic modulus of the adhesive layer is 1 × 10 ³ to 1 × 10 ⁶ Pa, and the tensile storage elastic modulus of the adhesive layer at 25 ° C. after irradiating the surface of the adhesive layer with active energy rays is 1 × 10 ^The adhesive sheet is ³ to 1 × 10 ⁶ Pa, and the tensile storage elastic modulus of the adhesive layer at 100 ° C. after the curing reaction is 2 × 10 ⁴ Pa or more.

  The adhesive sheet of the present invention has a surface that suppresses swelling and floating of the bonding member, which is caused by outgas from the surface of the molded product, residual stress of the bonding member, and the like, and does not transmit active energy rays. Since it can be affixed to the body, it can greatly contribute to the production of resin molded products used for the exterior of home appliances, the exterior of mobile terminals, the interior and exterior of automobiles, and the like.

The adhesive sheet of the present invention is an adhesive sheet used for bonding two or more adherends having a surface that does not transmit active energy rays, and is 25 ° C. before irradiating the surface of the adhesive layer with active energy rays. The tensile storage elastic modulus of the adhesive layer is 1 × 10 ³ to 1 × 10 ⁶ Pa, and the tensile storage elastic modulus of the adhesive layer at 25 ° C. after irradiating the surface of the adhesive layer with active energy rays is 1 ×. 10 ³ to 1 × 10 ⁶ Pa, and the tensile storage modulus of the adhesive layer at 100 ° C. after the curing reaction is 2 × 10 ⁴ Pa or more.

(Storage modulus)
The adhesive sheet of the present invention has a tensile storage elastic modulus of 1 × 10 ³ to 1 × 10 ⁶ Pa of the adhesive layer at 25 ° C. before irradiation with active energy rays, and the tensile strength of the adhesive layer at 25 ° C. after irradiation with active energy rays. An adhesive sheet having a storage elastic modulus of 1 × 10 ³ to 1 × 10 ⁶ Pa and a tensile storage elastic modulus of the adhesive layer at 100 ° C. after the curing reaction of 2 × 10 ⁴ Pa or more is used.

The tensile storage elastic modulus of the adhesive layer at 25 ° C. before irradiation with the active energy ray is preferably 1 × 10 ^{4 to} 5 × 10 ⁵ Pa, and pressure sensitive without heating to the first adherend. It is more preferable that the pressure is 5 × 10 ^{4 to} 5 × 10 ⁵ Pa in order to suppress adhesion and crushing only from the end face when the adhesive sheet is stored.

The tensile storage elastic modulus of the adhesive layer at 25 ° C. after irradiation with the active energy ray is preferably 1 × 10 ^{4 to} 5 × 10 ⁵ Pa, and pressure sensitive without heating to the second adherend. While being able to adhere | attach, when it heat-pastes, it does not become too soft, and it is 5 * 10 < ⁴ > -5 * 10 < ⁵ > Pa in order to suppress the expansion | swelling and floating by the outgas from a 1st and 2nd adherend and a residual stress. It is more preferable that

The tensile storage elastic modulus of the adhesive layer at 100 ° C. after the curing reaction is preferably 5 × 10 ⁴ to 1 × 10 ¹⁰ Pa, and when left in a humid heat environment for a long time and maintained in a heated state, 1 × 10 ⁵ to 1 × 10 ⁹ Pa is more preferable for suppressing swelling and floating due to outgas and residual stress from the first and second adherends.

In addition, the tensile storage elastic modulus of the adhesive layer at 25 ° C. after the curing reaction is preferably more than 1 × 10 ⁶ and 1 × 10 ¹² Pa or less, from the bonded first and second adherends. In order to obtain high bonding strength and difficulty in peeling under the usage environment of the molded article, 1 × 10 ⁷ to 1 × 10 ¹⁰ Pa is more preferable.

  The tensile storage elastic modulus is measured by a dynamic dynamic viscoelastic spectrum of tension. -40 to 150 under the conditions of a tension mode, a frequency of 1 Hz, a temperature increase rate of 3 ° C./min, and a load strain of 0.05%, using a TS Instruments viscoelasticity measuring device “RSA III”. The tensile storage elastic modulus (E ′) in the temperature range up to 0 ° C. is measured.

(Resin composition)
The adhesive layer of the adhesive sheet of the present invention is preferably made of a resin composition containing at least one kind of polymerizable resin.

(Polymerizable resin)
Examples of the polymerizable resin include resins in which monomers having a polymerizable functional group such as acrylic resin, urethane resin, phenol resin, and polyester resin are copolymerized. Among them, an acrylic resin having excellent adhesive strength is used. It is preferable to do.
As said acrylic resin, what is obtained by superposing | polymerizing the monomer component containing a (meth) acryl monomer etc. can be used.

  Examples of the (meth) acrylic monomer include methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, t-butyl (meth) acrylate, and n-hexyl ( It has an alkyl group having 1 to 14 carbon atoms such as (meth) acrylate, n-octyl (meth) acrylate, isooctyl (meth) acrylate, isononyl (meth) acrylate, cyclohexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate and the like. (Meth) acrylate can be used, (meth) acrylate having an alkyl group having 4 to 9 carbon atoms is preferably used, and ethyl acrylate or n-butyl acrylate is preferably used alone or in combination. . It is easy to adjust the tensile storage elastic modulus of the adhesive layer after irradiation of active energy rays to the above range, and suppresses the swelling and floating of the adhesive sheet when heat-bonding, and the phase when other polymerizable resin is used in combination. In order to increase the solubility, it is more preferable to use 50% by mass or more of ethyl acrylate having 2 carbon atoms that is less affected by the steric hindrance of the alkyl group.

  The (meth) acrylic monomer having an alkyl group having 1 to 14 carbon atoms is used in a range of 60 to 95% by mass with respect to the total amount of monomer components used for producing the acrylic polymer. It is preferable to use it in the range of 80 to 90% by mass for improving pressure-sensitive adhesion without heating to the first and / or second adherend and increasing the adhesive strength after the curing reaction. .

  As the (meth) acrylic monomer, in addition to those described above, a (meth) acrylic monomer having a cationic polymerizable functional group such as an epoxy group, an oxetanyl group, a vinyl ether group, an episulfide group, an ethyleneimine group, or an oxazoline group. It is preferable to use a monomer, and particularly that having an epoxy group and / or an oxetanyl group is unlikely to cause a rapid curing reaction when active energy rays are irradiated to the adhesive layer surface of the adhesive sheet. It is preferable for maintaining pressure-sensitive adhesiveness to the adherend of No. 2.

  Specific examples of the vinyl monomer having an epoxy group and / or oxetanyl group include glycidyl acrylate, glycidyl methyl methacrylate, 4-hydroxybutyl acrylate glycidyl ether having an epoxy group, and oxetanyl group (3-ethyloxetane). -3-yl) methyl acrylate, 3,4-epoxycyclohexylmethyl methacrylate, etc. can be used, among which the use of glycidyl acrylate or glycidyl methyl methacrylate having an epoxy group is an adhesive layer after the curing reaction The tensile storage elastic modulus is adjusted to the above range so that it does not become too soft, and is particularly preferable for suppressing swelling and floating due to outgas and residual stress from the adherend when left in a wet heat environment.

  The acrylic copolymer has an epoxy equivalent of 500 to 20,000 g / eq. In the range of 2,000 to 15,000 g / eq. Is more preferable, 5,000 to 12,000 g / eq. It is possible to adjust the tensile storage elastic modulus of the adhesive layer after the curing reaction to the above range so that it is not too soft, there is little volume shrinkage during the curing reaction, and distortion remains at the adhesive interface. And it is further preferable when it suppresses reducing adhesive strength.

  Moreover, when using together other polymerizable resin which has an epoxy group, it is preferable that the sum total of the epoxy equivalent becomes the said range.

The total of the epoxy equivalents is calculated by calculating the molecular weight of the total vinyl monomers per mole of epoxy groups for the resin having each epoxy group [g / eq. ] Is calculated by multiplying the used fraction of the resin having each epoxy group. As a specific example, in the case of a resin composition composed of a resin A having an epoxy group, a resin B, and a resin C not containing an epoxy group, the total of epoxy equivalents is obtained by calculation from the following formula 1. In this case, other additive components and dilution solvents described later are not included in the calculation.
Mass parts of resin A having an epoxy group in the resin composition: x [parts by mass]
Mass parts of resin B having an epoxy group in the resin composition: y [mass parts]
Part by mass of resin C having no epoxy group in the resin composition: z [parts by mass]
Epoxy equivalent of resin A having an epoxy group in the resin composition: α [g / eq. ]
Epoxy equivalent of resin B having an epoxy group in the resin composition: β [g / eq. ]
Formula 1: Sum of epoxy equivalents [g / eq. ] = (Α × x + y × β) / (x + y + z)

  As the usage amount of the vinyl monomer having an epoxy group and / or oxetanyl group, it is preferable to adjust the usage amount so that the total of epoxy equivalents falls within the above range. When the acrylic copolymer is used alone as the polymerizable resin, it is preferably used in the range of 0.7 to 25% by mass, and used in the range of 5 to 15% by mass after the curing reaction. The tensile storage elastic modulus of the adhesive layer is adjusted to the above range so as not to be too soft, the volume shrinkage during the curing reaction is small, and it is further preferable for suppressing the adhesive strength from being reduced due to distortion remaining at the adhesive interface. .

  In addition to the acrylic copolymer, when other polymerizable resin described later is used in combination, it is more preferably used in the range of 0.2 to 5% by mass, and used in the range of 0.4 to 3% by mass. The tensile storage modulus of the adhesive layer after the curing reaction is adjusted to the above range so that it does not become too soft, the volume shrinkage associated with the curing reaction is small, strain remains at the adhesive interface, and the adhesive strength is reduced. It is further preferable to suppress the generation.

  As the (meth) acrylic monomer, in addition to those described above, a highly polar (meth) acrylic monomer is preferably used, and a nitrogen-containing vinyl monomer is more preferably used.

  As the nitrogen-containing vinyl monomer, it is preferable to use a nitrogen-containing vinyl monomer having an amino group, an amide group, a nitrile group or the like. Among them, as the nitrogen-containing vinyl monomer, an amide group and a nitrile group are used. Singly or in combination, it is easy to adjust the tensile storage elastic modulus of the adhesive layer after irradiation of active energy rays to the above range, and pressure sensitive adhesion without heating to the second adherend, The internal cohesive force of the acrylic copolymer is increased, and it is more preferable to suppress swelling and floating due to outgas and residual stress from the first and second adherends when it is heated and pasted.

  Examples of the nitrogen-containing vinyl monomer include N-vinyl-2-pyrrolidone, N-vinylcaprolactam, acrylonitrile, acryloylmorpholine, dimethylaminoethyl acrylate, N, N-dimethylacrylamide, N, N-diethylacrylamide, and N-isopropyl. Examples include acrylamide, dimethylaminopropyl acrylamide, and diacetone acrylamide. The nitrogen-containing vinyl monomer is preferably 0.5 to 40% by mass, more preferably 5 to 20% by mass, based on the total amount of monomer components used in the production of the acrylic polymer. Preferably, it is 8 to 15% by mass, the tensile storage elastic modulus of the adhesive layer after irradiation with active energy rays can be easily adjusted to the above range, and pressure sensitive adhesion can be performed without heating to the second adherend. In order to increase the internal cohesive force of the acrylic copolymer and not to become too soft when heated and bonded, it is more preferable for suppressing swelling and floating due to outgas and residual stress from the first and second adherends. .

  In the curing method using active energy rays, when the acrylic copolymer is cured by a cationic polymerization reaction, the acrylic copolymer includes 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl. It is preferable not to use a (meth) acrylic monomer having a hydroxyl group such as (meth) acrylate and 6-hydroxyhexyl (meth) acrylate. When the (meth) acrylate having a hydroxyl group is used, the cationic polymerization reaction proceeds immediately after irradiation with active energy rays, and the tensile storage elastic modulus of the adhesive layer after irradiation with active energy rays exceeds the above range. It becomes difficult to stick the adhesive sheet on the surface of the second adherend. The (meth) acrylic monomer having a hydroxyl group is preferably 0.05% by mass or less based on the total amount of the vinyl monomer component.

  The acrylic copolymer can be produced by polymerizing the monomer component by a known method such as a solution polymerization method, a bulk polymerization method, a suspension polymerization method, or an emulsion polymerization method. It is preferable to manufacture by a legal method in order to narrow the molecular weight distribution and increase the compatibility when other polymerizable resins are used in combination, and to obtain transparency of the obtained adhesive sheet.

  As the acrylic copolymer, those having a weight average molecular weight in the range of 10,000 to 1,000,000 are preferably used, and those having a weight average molecular weight in the range of 100,000 to 500,000 are before and after irradiation with active energy rays. It is easy to adjust the tensile storage elastic modulus of the adhesive layer to the above range, and it can be pressure-sensitive bonded to the first and second adherends without heating, and is not too soft when heated and bonded. In addition, it is more preferable for suppressing swelling and floating due to outgas and residual stress from the second adherend. Moreover, when using other polymeric resin together, its compatibility is improved and it is more preferable when maintaining the transparency of an adhesive sheet.

The weight average molecular weight can be measured by gel permeation chromatograph (GPC). More specifically, as a GPC measurement device, “SC8020” manufactured by Tosoh Corporation can be used to measure and obtain the following GPC measurement conditions based on polystyrene conversion values.
(GPC measurement conditions)
Sample concentration: 0.5% by mass (tetrahydrofuran solution)
Sample injection volume: 100 μL
・ Eluent: Tetrahydrofuran (THF)
・ Flow rate: 1.0 mL / min
Column temperature (measurement temperature): 40 ° C
Column: “TSKgel GMHHR-H” manufactured by Tosoh Corporation
・ Detector: Differential refraction

  It is preferable to use a resin having a glass transition temperature of −30 to 50 ° C. of the acrylic copolymer, and the resin having a temperature of −10 to 30 ° C. has a tensile storage elastic modulus of the adhesive layer before and after irradiation with active energy rays. It is easy to adjust to the range, and can be pressure-sensitively bonded to the first and second adherends in an environment of 25 ° C. or higher, and is not too soft to be heat-bonded, and from the first and second adherends. It is more preferable for suppressing swelling and floating due to outgas and residual stress. The glass transition temperature is a single acrylic sheet molded into a sheet by the method described later, and is measured by a tensile dynamic viscoelastic spectrum. -40 to 150 ° C. under the conditions of a tension mode, a frequency of 1 Hz, a temperature rising rate of 3 ° C./min, and a load strain of 0.05%, using a TS Instruments viscoelasticity measuring device “RSA III”. The storage elastic modulus (E ′) and loss tangent in the temperature range up to are measured, and the peak temperature of the loss tangent is defined as the glass transition temperature of the acrylic copolymer.

  In adjusting the tensile storage elastic modulus to the above range, in addition to the polymerizable resin, one or more other polymerizable resins may be used in combination.

  The other polymerizable resin has one or more cationically polymerizable functional groups such as epoxy group, oxetanyl group, vinyl ether group, episulfide group, ethyleneimine group, oxazoline group in one molecule. preferable. Among them, it is preferable to use a polymerizable resin having an epoxy group in order to obtain high curing reactivity and high bonding strength after the curing reaction. As the polymerizable resin having an epoxy group, a compound having one or more epoxy groups in one molecule can be used. Specific examples include bisphenol A type epoxy resin, bisphenol F type epoxy resin, biphenyl type epoxy resin, tetramethylbiphenyl type epoxy resin, polyhydroxynaphthalene type epoxy resin, isocyanate-modified epoxy resin, 10- (2,5-dihydroxyphenyl). -9,10-dihydro 9-oxa-10-phosphaphenanthrene-10-oxide modified epoxy resin, phenol novolac type epoxy resin, cresol novolac type epoxy resin, hexanediol type epoxy resin, triphenylmethane type epoxy resin, tetraphenyl Ethane type epoxy resin, dicyclopentadiene-phenol addition reaction type epoxy resin, phenol aralkyl type epoxy resin, naphthol novolak type epoxy resin, naphthol alla Rukyle-type epoxy resin, naphthol-phenol co-condensed novolak-type epoxy resin, naphthol-cresol co-condensed novolac-type epoxy resin, aromatic hydrocarbon formaldehyde-modified phenolic resin-type epoxy resin, biphenyl-modified novolac-type epoxy resin, trimethylolpropane-type epoxy A resin, an alicyclic epoxy resin, an acrylic resin having an epoxy group, a polyurethane resin having an epoxy group, a polyester resin having an epoxy group, an epoxy resin having flexibility, and the like can be used. As the polymerizable resin having an epoxy group, among them, trimethylolpropane type epoxy resin and alicyclic epoxy resin can be used alone or in combination to increase the crosslink density and the elasticity of the adhesive layer after the curing reaction. It is more preferable in increasing the rate and adhesive strength, and suppressing swelling and floating due to outgas and residual stress from the molded product when left in a humid heat environment.

  The other polysynthetic resin is preferably a semi-solid resin having a softening point of 25 ° C. or lower, or a liquid resin at 25 ° C., and a resin having a B-type viscosity at 25 ° C. of 100,000 mPa or lower. More preferably, using a resin of 1,000 mPa or less makes it easy to adjust the tensile storage elastic modulus of the adhesive layer before and after irradiation of active energy rays to the above range when used in combination with the acrylic copolymer. It can be pressure-sensitively bonded to the first and second adherends without heating, and the amount of other polymerizable resin used can be suppressed to a small amount. It is more preferable for suppressing swelling and floating due to outgas and residual stress from the adherend 2.

  The epoxy equivalent of the other polysynthetic resin can be arbitrarily adjusted as long as the total epoxy equivalent is within the above range, and among them, 50 to 1,000 g / eq. It is preferable that it is 100-300 g / eq. This improves the tensile storage elastic modulus of the adhesive layer after the curing reaction, and swells and floats due to outgas and residual stress from the first and second adherends when left in a humid heat environment. It is more preferable to suppress the above.

  As said other polysynthetic resin, it is preferable to use what has the weight average molecular weight of the range of 50-1,000, and what has the weight average molecular weight of the range of 100-500 is the said acrylic copolymer and It is more preferable to improve the compatibility of the adhesive sheet, maintain the transparency of the adhesive sheet, and suppress the seepage of the adhesive sheet from the adhesive layer during the heat bonding after irradiation with the active energy ray.

  The amount of the other polymerizable resin to be used can be arbitrarily adjusted as long as the total epoxy equivalent is within the above range with respect to the acrylic copolymer, and among them, 5 to 60% by mass is used. It is preferable to use 20 to 50% by mass, while suppressing the seepage from the adhesive layer of the adhesive sheet during the heat-bonding after irradiation with the active energy ray, increasing the crosslinking density, and after the curing reaction It is more preferable for improving the tensile storage elastic modulus of the adhesive layer and suppressing swelling and floating due to outgas and residual stress from the first and second adherends when left in a humid heat environment.

(Polymerization initiator)
The initiator used for the curing reaction of the adhesive layer of the adhesive sheet of the present invention may be one that is activated by an external stimulus. For example, if the cationic polymerizable compound is used, the cationic polymerizable compound is used. It is preferable to use one having a functional group capable of reacting with the functional group.

  Moreover, there exist a photoinitiator and a thermal-polymerization initiator as said polymerization initiator, This may be used independently and may use 2 types together. Among these, in order to obtain a reaction at a low temperature and a good curing reaction, it is preferable to use a photopolymerization initiator whose reaction proceeds by light as an external stimulus. As a result, high bonding strength can be obtained without damaging the members to be laminated or by deforming the adherend due to distortion between the first and second adherends and without causing cracks in the adherend. I can do it.

  As the light, an appropriate light type such as ultraviolet light or visible light can be used, but it is preferable to use light having a wavelength of 300 nm to 420 nm.

  The photopolymerization initiator is not particularly limited as long as it is activated by light, and examples thereof include a radical photopolymerization initiator, a photocationic polymerization initiator, and a photoanion polymerization initiator. If a cationically polymerizable compound is used, it is preferable to use a photocationic polymerization initiator.

  The cationic photopolymerization initiator is not particularly limited as long as it can induce a ring-opening reaction of a cationically polymerizable functional group with light having a wavelength to be used, but with light having a wavelength of 300 to 370 nm, A compound that induces a ring-opening reaction of a cationically polymerizable functional group and is inactive in a wavelength region exceeding 370 nm is preferably used. Examples of such a compound include aromatic diazonium salts, aromatic iodonium salts, aromatic compounds, and the like. Onium salts such as group sulfonium salts.

  Specific examples of such onium salts include, for example, optomer SP-150, optomer SP-170, optomer SP-171 (all manufactured by ADEKA), UVE-1014 (manufactured by General Electronics), OMNICAT250, and OMNICAT270 (all Also IGM Resin), IRGACURE290 (BASF), Sun-Aid SI-60L, Sun-Aid SI-80L, Sun-Aid SI-100L (all from Sanshin Chemical Industry Co., Ltd.), CPI-100P, CPI-101A, CPI-200K (Both manufactured by San Apro).

  In addition, the said cationic photopolymerization initiator may be used independently and may be used together 2 or more types. Furthermore, two-step curing may be performed using a plurality of photocationic polymerization initiators having different effective active wavelengths.

  The photocationic polymerization initiator may be used in combination with an anthracene-based, thioxanthone-based, or other sensitizer as necessary.

  The blending ratio of the photocationic polymerization initiator is preferably 0.001 to 30 parts by mass with respect to 100 parts by mass of the photocationic polymerization initiator, and 0.01 to 20 parts by mass. It is preferable to use in the range, and when adjusting the tensile storage elastic modulus of the adhesive layer after irradiation with the active energy ray to the above range, it is more preferable to use in the range of 0.1 to 10 parts by mass. If the blending ratio of the photocationic polymerization initiator is too small, the crosslinking density after the curing reaction is insufficient, the tensile storage elastic modulus of the adhesive layer is out of the above range, and swelling and floating in a humid heat environment are suppressed. On the other hand, if the bonding strength required is insufficient, on the other hand, the cationic polymerization reaction of the adhesive layer after irradiation with active energy rays proceeds rapidly, and the tensile storage elastic modulus is out of the above range. The pressure-sensitive adhesive time may be too short.

  The adhesive layer of the adhesive sheet of the present invention increases the crosslink density after the curing reaction, adjusts the storage elastic modulus to the above range, and suppresses swelling and floating in a moist heat environment. A post-curing step may be performed after heat bonding to the adherend. As the leaving condition of the post-curing step, 100 ° C. or lower is preferable, and in order to suppress deformation of the first and second adherends due to heat, it is more preferable to pass the post-curing step for about 1 hour at 80 ° C. or lower. .

  In addition to the resin composition, as other additives, adhesion promoter, surface conditioner, leveling agent, antifoaming agent, plasticizer, tackifier resin, antioxidant, light stabilizer, hydrolysis inhibitor, thickening agent In order to control the curing agent and the curing reaction, additives such as known catalysts can be used as necessary.

  In the molded part on which the adhesive sheet of the present invention is bonded, an electromagnetic signal such as an automobile emblem or an electromagnetic wave such as a millimeter wave is passed, or a high frequency electric pulse such as a flexible printed board is passed in the vicinity to pass an electrical signal. In applications such as reading, a polyolefin resin, an inorganic filler, or the like may be added for the purpose of adjusting the dielectric loss tangent or relative dielectric constant of the adhesive sheet.

  The polyolefin resin is preferably an olefin resin such as polyethylene resin or polypropylene resin having a relative dielectric constant of about 2-3, or a rubber resin such as isoprene-based resin or butadiene-based resin, and is compatible with the thermoplastic resin or liquid resin. For the purpose of improving solubility, a part of the side chain may be chlorinated or modified with carboxylic acid to partially improve the polarity. In addition, by introducing an epoxy group, an oxetanyl group, or the like into the molecule of the polyolefin resin, it is preferable for increasing the tensile storage elastic modulus of the adhesive layer after the curing reaction by incorporating it into the curing reaction system.

As the inorganic filler, it is preferable to use an inorganic filler having a dielectric loss tangent of about 10 ⁻⁴ to 10 ⁻⁵ such as boron nitride, forteslite, cordierite, silica, magnesium oxide, alumina, and the like. It is more preferable to use silica that is excellent in compatibility and can enhance the transparency of the adhesive sheet.

  As the inorganic filler, those having an arbitrary shape such as a spherical shape or a crushed shape can be used, and in order to enhance compatibility with the polymerizable resin, titanate coupling, aluminate coupling or silane coupling is provided on the surface. You may use what surface-treated.

  The amount of the polyolefin resin or inorganic filler used is preferably 1 to 50 parts by mass, and preferably 5 to 20 parts by mass relative to 100 parts by mass of the polymerizable resin. It is more preferable because it is possible to suppress a decrease in pressure-sensitive adhesiveness to the surface of the adherend and a decrease in adhesiveness after the curing reaction while reducing the rate and dielectric loss tangent.

  As the particle size of the inorganic filler, it is preferable to use a particle having a 50% cumulative sieve distribution particle size of 10 nm to less than 50 μm, more preferably 10 nm to 20 μm, and more preferably 1 to 10 μm. It is particularly preferable to increase the transparency of the adhesive sheet and achieve both good dispersibility of the inorganic filler and ease of coating. The 50% particle size under the cumulative sieve distribution of the inorganic filler is a numerical value measured using isopropanol as a dispersion medium using a laser diffraction particle size distribution analyzer SALD-3100 manufactured by Shimadzu Corporation. Can do.

  Examples of the solvent include ester solvents such as methyl acetate, ethyl acetate, propyl acetate, and butyl acetate; ketone solvents such as acetone, methyl ketyl ketone, methyl isobutyl ketone, diisobutyl ketone, and cyclohexanone; and toluene and xylene. Aromatic hydrocarbon solvents and the like can be used.

(Adhesive sheet)
The adhesive layer of the adhesive sheet of the present invention can be produced by molding a resin composition in which a polymerizable resin, a polymerization initiator, other additives, a solvent and the like are uniformly mixed into a sheet shape.

  When mixing the above-described components to produce the resin composition, a dissolver, butterfly mixer, BDM biaxial mixer, planetary mixer, etc. can be used as necessary, and a dissolver, butterfly mixer can be used. Preferably, when using the inorganic filler, it is preferable to use a planetary mixer in order to improve the dispersibility thereof. Also, in the process of manufacturing the adhesive sheet, in order to suppress pinholes that occur during solvent drying and not to deteriorate the transparency and adhesive performance of the adhesive sheet, vacuum defoaming, centrifugal defoaming, etc., as necessary A mixer or a liquid feed pump having a defoaming function may be used.

  The adhesive sheet of the present invention is obtained by, for example, applying the resin composition obtained by uniformly mixing the polymerizable resin, the polymerization initiator, other components, a solvent, and the like to the surface of the release liner, for example, and drying the adhesive composition. Sheets can be manufactured.

  The drying is preferably performed at a temperature of about 40 to 120 ° C., more preferably about 50 to 90 ° C., in order to suppress the progress of the curing reaction by the polymerization initiator.

  Examples of the release liner include paper such as craft paper, glassine paper, and high-quality paper, resin films such as polyethylene, polypropylene (OPP, CPP), and polyethylene terephthalate, laminated paper obtained by laminating the paper and resin film, Paper that has been subjected to sealing treatment with clay, polyvinyl alcohol, or the like can be used with one or both sides subjected to a release treatment such as a silicone-based resin. It is preferable to use what was made in order to improve the transparency of the adhesive sheet of this invention.

  The adhesive sheet of the present invention may be sandwiched by another arbitrary release liner until it is used in the bonding step.

  The thickness of the adhesive layer of the adhesive sheet of the present invention is preferably 5 to 1,000 μm, and can be pressure-sensitively bonded to the first and second adherends in an environment of 25 ° C. or higher, and the adhesive sheet In order to avoid the deterioration of the transparency due to the protrusion of the adhesive layer or the thickening of the film during storage, the thickness is preferably 30 to 150 μm.

  Further, in order to reduce the amount of the solvent remaining after drying, two or more adhesive layers coated and dried on different release liners may be bonded together to obtain an adhesive sheet having a predetermined thickness. In this case, in order to suppress the separation, it is preferable to bond the release liners having different release forces.

  The adhesive layer of the adhesive sheet of the present invention preferably has a gel fraction in the range of 5 to 70% by mass in the stage before irradiation with active energy rays, and is in the range of 20 to 50% by mass. It is easy to adjust the tensile storage elastic modulus of the adhesive layer before and after irradiation of active energy rays to the above range, and pressure sensitive adhesion can be performed without heating to the first and second adherends. When pasting, it does not become too soft, and it is more preferable for suppressing swelling and floating due to outgas and residual stress from the first and second adherends.

  The gel fraction was determined by immersing the adhesive layer of the adhesive sheet of the present invention having a release liner laminated on one side in toluene adjusted to 23 ° C. for 24 hours, and remaining in the solvent. The mass after drying of the layer and the value calculated based on the following formula.

Gel fraction (mass%) = {(mass of adhesive layer of adhesive sheet remaining without being dissolved in toluene) / (mass of adhesive layer of adhesive sheet before immersion in toluene)} × 100
The mass of the adhesive layer of the adhesive sheet constituting the adhesive sheet before immersion is a value obtained by subtracting the mass of the release liner used for the production from the mass of the test piece. In addition, the mass of the adhesive layer of the remaining adhesive sheet refers to a value obtained by subtracting the mass of the release liner from the mass after the residue is dried.

  In addition, the adhesive layer of the adhesive sheet of the present invention preferably uses a gel fraction after the curing reaction in the range of 50 to 99% by mass, and uses in the range of 70 to 90% by mass. The crosslink density is high, the tensile storage modulus of the adhesive layer after the curing reaction is improved, and the outgas and residual stress from the first and second adherends when left in a moist heat environment. It is more preferable for suppressing swelling and floating due to the above.

The glass transition temperature of the adhesive layer of the adhesive sheet of the present invention before irradiation with active energy rays is preferably -30 to 50 ° C., and −10 to 30 ° C. is before irradiation with active energy rays. It is preferable because the tensile storage modulus of the adhesive layer can be easily adjusted to the above range, and pressure-sensitive adhesion can be performed without heating the first adherend. The glass transition temperature after curing is preferably 0 ° C. or higher, and more preferably 30 to 250 ° C. in order to suppress cracking of the adhesive layer in a cold environment and to suppress swelling and floating when left in wet heat. . In addition, a glass transition temperature is measured with the dynamic viscoelastic spectrum of tension | pulling about the adhesive bond layer of an adhesive sheet. -40 to 150 ° C. under the conditions of a tension mode, a frequency of 1 Hz, a temperature rising rate of 3 ° C./min, and a load strain of 0.05%, using a TS Instruments viscoelasticity measuring device “RSA III”. The storage elastic modulus (E ′) and the loss tangent in the temperature range up to are measured, and the peak temperature of the loss tangent is defined as the glass transition temperature of the adhesive layer of the adhesive sheet.

  When using the transparent resin sheet mentioned later as a 1st to-be-adhered body, it is preferable to use the adhesive sheet of this invention that the total light transmittance Tt of an adhesive sheet is 80 to 99%. More preferably, the total light transmittance Tt is 90 to 99%. Moreover, as said adhesive sheet, it is preferable to use what has a haze of 0 to 3%, and it is more preferable to use what has a haze of 0 to 2%. If it is an adhesive sheet having the total light transmittance Tt and haze in the above-mentioned range, an excellent appearance can be given without impairing the design decorated on the second adherend surface.

  The total light transmittance Tt and haze were two resin sheets made of polycarbonate having a thickness of 1 mm or less, a total light transmittance Tt of 90% or more and a haze of 0.5% or less, and the release liner was removed. After irradiating the surface of the adhesive layer of the adhesive sheet of the present invention with an activation energy ray and adhering to the two resin sheets so that bubbles do not enter, after a post-curing step at 70 ° C. for 1 hour, The total light transmittance Tt and haze when measured with an arbitrary total light transmittance meter according to JIS K7136.

  In the adhesive sheet of the present invention, the first and second adherends preferably have a peel adhesive strength of 0.5 N / 20 mm or more, preferably 2 N / 20 mm or more, before and after irradiation with active energy rays. It is more preferable to suppress swelling and floating due to outgas from the first and second adherends when heating and pasting.

  Further, the peel adhesive strength after the curing reaction of the adhesive sheet is preferably 5 N / 20 mm or more, and that it is 8 N / 20 mm or more when left in a humid heat environment. It is more preferable for suppressing swelling and floating due to outgas and residual stress from the adherend.

  The peel adhesive strength before irradiation with the active energy ray was determined by applying a test piece obtained by bonding a polyester film having a thickness of 50 μm to one side of the adhesive sheet cut to a width of 20 mm and a length of 100 mm at 23 ° C. and 50% RH. Affixed to a polycarbonate plate with a thickness of 0.15mm under the environment, and then applied one reciprocating pressure at a speed of 300mm / min with a 2kg roller, then a polyester film at a pulling speed of 50mm / min in a 180 ° direction within 1 minute. Measure the adhesive strength when peeling off.

The peel adhesive strength after irradiation with the active energy ray was obtained by removing the release liner on one side from a test piece bonded to a polyester film having a thickness of 50 μm on one side of the adhesive sheet cut to a width of 20 mm and a length of 100 mm. Thereafter, the surface of the adhesive layer was irradiated with an ultraviolet ray with an intensity of 290 mW / cm ² and an irradiation amount of 500 mJ / cm ² by an ultraviolet irradiation lamp, and after 20 minutes from the ultraviolet irradiation in an environment of 23 ° C. and 50% RH, Similarly, the adhesive strength is measured.

  The peel adhesive strength after the curing reaction was further affixed to a polycarbonate plate having a thickness of 0.15 mm 20 minutes after UV irradiation, and was pressed once at a rate of 300 mm / min with a 2 kg roller, and then at 70 ° C. After storing for 1 hour, the adhesive strength is measured in the same manner.

  The adhesive sheet of the present invention may have a structure in which the resin composition is laminated on both sides of a base material, and the base material has a thickness of 1/2 or less with respect to the total thickness of the adhesive sheet. It is preferable to use it. Thereby, the handleability of the adhesive sheet is improved, and when the adhesive sheet is cut, the adhesive layer does not protrude and has excellent dimensional stability, which is preferable. As the substrate, any film or mesh material such as polyethylene terephthalate, polybutylene terephthalate, polyimide, polyphenylene sulfide, polyphenylene ether, polypropylene, polyethylene, polystyrene, etc. can be used, and the thickness is 1 to 30 μm. It is preferable to use a material having a thickness of 2 μm to 15 μm.

  For example, the resin composition is laminated on both surfaces of the base material, for example, the resin composition is directly applied to both surfaces of the base material to dry the solvent, or the solvent is applied to the surface of the release liner and dried. Then, it can manufacture by making it pressure-paste on both the surfaces of the said base material.

(Adherent)
As a 1st to-be-adhered body which bonds the adhesive sheet of this invention, bonding members, especially laminate materials, such as arbitrary resin-made sheets and metal sheets which are impervious to active energy rays can be used.

  Examples of the material of the resin sheet include polycarbonate, polymethyl methacrylate, an alloy of polycarbonate and acrylonitrile-butadiene-styrene copolymer, polyethylene terephthalate, polybutylene terephthalate, polyimide, polyphenylene sulfide, polyphenylene ether, polypropylene, polyethylene, polystyrene, and the like. Any material can be used. It is preferable to use polycarbonate or polymethyl methacrylate, which is excellent in stretchability by heating, transparency and gloss. In addition, an arbitrarily colored resin sheet may be used, and when ultraviolet rays are used as active energy rays, ultraviolet rays are applied to the adhesive layer of the adhesive sheet on the back surface even if ultraviolet rays are irradiated from the surface of the resin sheet. This is preferable because the adhesive sheet of the present invention can be suitably used.

  Moreover, when the molded article which affixes the said resin-made sheet is used outdoors, it is preferable to use the resin-made sheet | seat with which the ultraviolet cut agent was kneaded or the ultraviolet cut layer was laminated | stacked. In the case of the resin sheet, when ultraviolet rays are used as active energy rays, the amount of ultraviolet rays reaching the adhesive layer of the adhesive sheet on the back surface is small even when the ultraviolet ray is irradiated from the surface of the resin sheet, Since an adhesive sheet can be used conveniently, it is preferable.

  As the material of the metal sheet, an arbitrary material such as a sheet of aluminum, copper, stainless steel, nickel, titanium, gold, silver, or a resin sheet on which these metals are vapor-deposited or plated is used. be able to.

  The thickness of the first adherend is preferably a sheet having a thickness of 0.05 to 2 mm. For the purpose of bonding to the surface of the molded article, which is the second adherend, and preventing scratches, the thickness is 0.00. It is more preferable to use a 1 to 0.5 mm sheet.

  It is preferable that an arbitrary hard coat layer, a mat layer or the like is directly applied to the surface of the first adherend or laminated on the surface by a coextrusion method or the like.

  An arbitrary colored decorative print layer may be provided on the entire surface or a part of the surface of the first adherend.

  As a 2nd to-be-adhered body which bonds the adhesive sheet of this invention, arbitrary activated energy rays can use the molded article which is impervious.

  As the material of the second adherend, polycarbonate, polymethyl methacrylate, alloy of polycarbonate and acrylonitrile-butadiene-styrene copolymer, polyethylene terephthalate, polybutylene terephthalate, polyimide, polyphenylene sulfide, polyphenylene ether, polypropylene, polyethylene Any material such as polystyrene or a material bonded to metal can be used. From the ease of moldability, polycarbonate, polymethyl methacrylate, polycarbonate and acrylonitrile-butadiene-styrene copolymer alloy, etc. can be used. It is preferable to use it. Further, an arbitrarily colored adherend may be used, and in the case where ultraviolet rays are used as the active energy ray, the adhesive on the adhesive sheet on the back side is irradiated with ultraviolet rays from the surface side of the second adherend. The amount of ultraviolet rays reaching the layer is small, which is preferable because the adhesive sheet of the present invention can be suitably used.

  The front surface and the back surface of the second adherend may be subjected to metal deposition such as aluminum or chromium or colored printing with printing ink.

  As the second adherend, a molded product produced by any molding method such as injection molding, extrusion molding, blow molding, vacuum molding, pressure molding, compression molding or the like can be used.

The method for producing the molded article includes the step [1] of bonding the adhesive layer of the adhesive sheet of the present invention and the first adherend by pressure-sensitive adhesion without heating, and the adhesive layer of the adhesive sheet. Step [2] of irradiating the other surface of the substrate with active energy rays to initiate polymerization [2], attaching the laminate of the adhesive sheet to a molding machine, and heating the surface of the first adherend while the laminate is heated A step [3] of applying a second adherend to the surface of the adhesive layer by applying the second adherend, and post-curing a laminate in which the first adherend and the second adherend are bonded with the adhesive sheet It is a manufacturing method including in order of the process [4] to perform. As the second adherend, two or more kinds of adherends may be bonded simultaneously in the step [3].
The step [1] is preferably performed in an environment of 0 ° C. to 50 ° C., and the adhesive sheet of the present invention is performed in an environment of 10 ° C. to 40 ° C. based on the fact that it can be bonded without heating. Is more preferable.
In the step [3], it is preferable that the second adherend is pressed onto the surface of the adhesive layer of the laminate, and the first adherend is applied while being stretched.

  As a specific example of the adhesive sheet bonding method of the present invention, the release liner on one side is removed from the adhesive sheet, and the first adherend is bonded to the first adherend in a room temperature atmosphere, and then cut into an arbitrary size. To the second adherend, the other release liner is removed and the adhesive layer is exposed, or the release liner is stuck, and the release liner is passed through to the surface of the adhesive layer. After irradiating the active energy ray, it is attached to an apparatus (for example, an injection-in-mold molding machine, a vacuum molding machine, a pressure molding machine, etc.) that performs bonding. Thereafter, within about 20 to 60 minutes after irradiation with the active energy ray, the adhesive sheet of the present invention together with the first adherend is heated to about 100 to 160 ° C. in a room temperature atmosphere or with a far infrared heater or the like. However, it is bonded to the second adherend surface with a pressure of about 0.1 to 0.2 MPa. After bonding, the excess adhesive sheet and the first adherend are cut and removed, and left as an after-curing in an environmental atmosphere of about 70 ° C. for about 1 hour to produce a molded product.

As the active energy ray, light rays such as ultraviolet rays, infrared rays, and electron beams are used. When a photocation initiator is used as the polymerization initiator, it is possible to use the active energy rays by ultraviolet rays with a simple apparatus. Irradiation is possible and preferable. An arbitrary irradiation device can be used for the ultraviolet irradiation, and an ultraviolet lamp such as a high-pressure mercury lamp, a low-pressure mercury lamp, a metal halide lamp, an ultraviolet LED lamp, or an ultraviolet electrodeless lamp can be used. As irradiation conditions of ultraviolet rays, an irradiation intensity of 100 to 500 mW / cm ² m is preferable, and as an integrated irradiation amount, an irradiation amount of 100 to 1,000 mJ / cm ² is preferable. When the irradiation conditions are satisfied, it is easy to adjust the tensile storage elastic modulus of the adhesive layer after irradiation of active energy rays to the above range, and the curing reaction does not proceed immediately after irradiation, and the bonding with the second adherend is performed. Pressure-sensitive adhesiveness can be maintained until the process.

  The adhesive sheet of the present invention activated by light or the like is hard to proceed with a curing reaction at room temperature before irradiation with active energy rays, has good storage stability, and after irradiation with activation energy rays. Can be stuck to the second adherend without post-curing reaction, and can be post-cured by heating at 100 ° C. or lower. Moreover, an active energy ray may be used independently and may be used in combination.

  In the wet heat environment, the manufactured molded product is left for the purpose of evaluating the reliability of the molded part in which the first adherend and the second adherend are bonded with the adhesive sheet of the present invention. The The wet heat environment includes, for example, 60 ° C. and 90% RH, 85 ° C. and 85% RH, and is left for a period of about 2 to 72 hours, and the presence or absence of swelling or floating is observed.

  The molded product obtained by bonding the bonding member, which is the first adherend, and the second adherend with the adhesive sheet of the present invention can be applied to the exterior of home appliances, the exterior of mobile terminals, the interior and exterior of automobiles, and the like. It is suitably used for the resin molded product used. These are parts molded in a three-dimensional direction by injection molding, extrusion molding, etc., and a bonding member having a hard coat layer and a mat layer on the surface as an anti-scratch surface is bonded with the adhesive sheet of the present invention. It is excellent in appearance quality because it suppresses the occurrence of blistering and lifting due to outgassing and residual stress of the bonding material during heating bonding, and also suppresses the occurrence of blistering and lifting even when left in a humid heat environment. It is a molded product.

  Hereinafter, the present invention will be described in detail with reference to examples and comparative examples.

<Preparation of acrylic copolymer (A)>
In a reaction vessel equipped with a stirrer, a cold flow cooler, a thermometer, a dropping funnel and a nitrogen gas inlet, 86.3 parts by mass of ethyl acrylate, 11 parts by mass of N-isopropylacrylamide, 2 parts by mass of acrylonitrile, 0.7 mass of glycidyl methacrylate Part and 0.22 parts by mass of 2,2′-azobisisobutylnitrile as a polymerization initiator are dissolved in 455 parts by mass of methyl ethyl ketone, and after nitrogen substitution, polymerized at 80 ° C. for 8 hours to obtain a solid content of 18% by mass, An acrylic copolymer (A) having a weight average molecular weight of 350,000 was obtained. The epoxy equivalent was 14,200 g / eq. The glass transition temperature was 11 ° C.

<Preparation of acrylic copolymer (B)>
In a reaction vessel equipped with a stirrer, a cold flow cooler, a thermometer, a dropping funnel and a nitrogen gas inlet, 52 parts by mass of ethyl acrylate, 24.7 parts by mass of n-butyl acrylate, 19 parts by mass of methyl methacrylate, 2 parts by mass of acrylonitrile, Dissolve 2.3 parts by mass of glycidyl methacrylate and 0.2 parts by mass of 2,2′-azobisisobutylnitrile as a polymerization initiator in 567 parts by mass of methyl ethyl ketone, and after purging with nitrogen, polymerize at 80 ° C. for 8 hours. An acrylic copolymer (B) having a solid content of 15% by mass and a weight average molecular weight of 850,000 was obtained. The epoxy equivalent was 4,760 g / eq. The glass transition temperature was 12 ° C.

<Preparation of acrylic copolymer (C)>
In a reaction vessel equipped with a stirrer, cold flow cooler, thermometer, dropping funnel and nitrogen gas inlet, n-butyl acrylate 56 parts by mass, cyclohexyl acrylate 20 parts by mass, methyl acrylate 10 parts by mass, diacetone acrylamide 4 parts by mass, 10 parts by mass of glycidyl methacrylate and 0.2 part by mass of 2,2′-azobisisobutylnitrile as a polymerization initiator are dissolved in 300 parts by mass of methyl ethyl ketone, and after substitution with nitrogen, polymerization is performed at 80 ° C. for 8 hours to obtain a solid content. An acrylic copolymer (C) having 25% by mass and a mass average molecular weight of 500,000 was obtained. The epoxy equivalent was 1,320 g / eq. The glass transition temperature was -11 ° C.

<Preparation of acrylic copolymer (D)>
In a reaction vessel equipped with a stirrer, a cold flow cooler, a thermometer, a dropping funnel and a nitrogen gas inlet, n-butyl acrylate 56 parts by mass, cyclohexyl acrylate 20 parts by mass, methyl acrylate 10 parts by mass, diacetone acrylamide 12 parts by mass, 2 parts by mass of hydroxyethyl acrylate and 0.2 part by mass of 2,2′-azobisisobutylnitrile as a polymerization initiator are dissolved in 70 parts by mass of methyl ethyl ketone and 47 parts by mass of ethyl acetate. Polymerization was carried out for 8 hours to obtain an acrylic copolymer (D) having a solid content of 46% by mass and a weight average molecular weight of 750,000. The epoxy equivalent was 0 g / eq, and the hydroxyl equivalent was 6,670 g / eq. The glass transition temperature was −14 ° C.

Example 1
As a polymerizable resin, 555 parts by mass of the acrylic copolymer (A) solution and CEL-2021P (manufactured by Daicel Corporation, bifunctional alicyclic epoxy resin, epoxy equivalent 131 g / eq., B at 25 ° C. environment) 30 parts by mass of a mold viscosity of 245 mPa · s) and 8 parts by mass of CPI-100P (manufactured by San Apro Co., sulfonium salt system, solid content: 50% by mass) as a polymerization initiator are mixed to obtain a resin composition (a-1). It was. The total epoxy equivalent of the resin composition (a-1) is 9,980 g / eq. Met.

Next, the resin composition (a-1) is applied to the surface of a release liner (one surface of a polyethylene terephthalate film having a thickness of 75 μm is peeled off with a silicone compound) using a cylindrical metal applicator, It coated so that the thickness after drying might be set to 50 micrometers.
Further, the coated product was put into a dryer at 50 ° C. for 3 minutes, and then put into a dryer at 75 ° C. for 5 minutes and dried to obtain an adhesive sheet having a thickness of 50 μm.
Adhesion obtained by coating on the surface of another release liner (one side of a polyethylene terephthalate film having a thickness of 38 μm was peeled off with a silicone compound) so that the thickness after drying was 50 μm in the same manner as described above. The sheet was bonded to the adhesive sheet to obtain an adhesive sheet (A-1) having a thickness of 100 μm.

(Example 2)
The amount of the acrylic copolymer (A) used as the polymerizable resin was 333 parts by mass, the amount of CEL-2021P used was 40 parts by mass, and the resin composition (a-2) was obtained. Same as Example 1 except that another release liner (one side of a 38 μm thick polyethylene terephthalate film was peeled off with a silicone compound) was bonded to the surface of one adhesive sheet without bonding. Thus, an adhesive sheet (A-2) having a thickness of 50 μm was obtained. The total epoxy equivalent of the resin composition (a-2) is 8,570 g / eq. Met.

(Example 3)
Example 1 except that the amount of the acrylic copolymer (A) used as the polymerizable resin is 444 parts by mass and the amount of CEL-2021P used is 20 parts by mass to obtain a resin composition (a-3). Similarly, an adhesive sheet (A-3) having a thickness of 100 μm was obtained. The total epoxy equivalent of the resin composition (a-3) is 11,390 g / eq. Met.

(Example 4)
As a polymerizable resin, Denacol EX321L (manufactured by Nagase ChemteX Corporation, trimethylolpropane triglycidyl ether, epoxy equivalent 130 g / eq., B-type viscosity 300 mPa · s at 25 ° C.) is used instead of CEL-2021P. And except having set it as the resin composition (a-4), it carried out similarly to Example 1, and obtained the adhesive sheet (A-4) with a thickness of 100 micrometers. The total epoxy equivalent of the resin composition (a-4) is 9,980 g / eq. Met.

(Example 5)
The same procedure as in Example 1 was conducted except that 467 parts by mass of the acrylic copolymer (B) solution and 30 parts by mass of CEL-2021P were used as the polymerizable resin to obtain a resin composition (b-1). An adhesive sheet (B-1) having a thickness of 100 μm was obtained. The total epoxy equivalent of the resin composition (b-1) is 3,370 g / eq. Met.

(Example 6)
As a polymerizable resin, only 400 parts by mass of the acrylic copolymer (C) solution was used to obtain a resin composition (c-1), and two adhesive sheets were not bonded, and one adhesive sheet was used. In the same manner as in Example 1, except that another release liner (one surface of a polyethylene terephthalate film having a thickness of 38 μm was peeled off by a silicone compound) was bonded to the surface of the adhesive sheet ( C-1) was obtained. The total epoxy equivalent of the resin composition (c-1) is 2,210 g / eq. Met.

(Comparative Example 1)
Example 1 except that the amount of the acrylic copolymer (A) used as the polymerizable resin was 500 parts by mass, the amount of CEL-2021P used was 10 parts by mass, and the resin composition (a-5) was used. In the same manner as above, an adhesive sheet (A-5) having a thickness of 100 μm was obtained. The total epoxy equivalent of the resin composition (a-5) is 12,800 g / eq. Met.

(Comparative Example 2)
An adhesive sheet having a thickness of 100 μm was used in the same manner as in Example 1 except that 152 parts by mass of the acrylic copolymer (D) solution was used as the polymerizable resin to obtain a resin composition (d-1). D-1) was obtained. The total epoxy equivalent of the resin composition (d-1) is 9,940 g / eq. Met.

(Comparative Example 3)
To 100 parts by mass of the acrylic copolymer (D) solution, 0.8 parts by mass of Takenate D110N (manufactured by Mitsui Chemicals, trimethylolpropane modified xylylene diisocyanate, solid content 75% by mass) as an isocyanate crosslinking agent. The resin composition (d-2) which does not use a polymerization initiator only by adding was obtained. In the same manner as in Example 1, an adhesive sheet having a thickness of 100 μm was prepared and left at 23 ° C. for 7 days to obtain an adhesive sheet (D-2). The total epoxy equivalent of the resin composition (d-2) was 0 g / eq. Met.

(Comparative Example 4)
As a polymerizable resin, only Finetac RX-301 (manufactured by DIC Corporation, UV curable adhesive, solid content 60% by mass) was used as a resin composition (e-1), and a polymerization initiator was used. An adhesive sheet (E-1) having a thickness of 100 μm was obtained in the same manner as Example 1 except that it was not added additionally. The total epoxy equivalent of the resin composition (e-1) is 0 g / eq. Met.

(Comparative Example 5)
Instead of the acrylic copolymer (A), 250 parts by mass of jER1256B40 (Mitsubishi Chemical Corporation, phenoxy resin, epoxy equivalent 8,000 g / eq.) Was used as the polymerizable resin, and the resin composition (f-1 Except for the above, an adhesive sheet (F-1) having a thickness of 100 μm was obtained in the same manner as in Example 1. The total epoxy equivalent of the resin composition (f-1) is 5,640 g / eq. Met.

  In addition, the said resin composition of Examples 1-5, Comparative Examples 1-2, and Comparative Example 5 has a photoinitiator, and acrylic copolymers (A)-(C) and an epoxy resin Has an epoxy group as a reactive site, and the acrylic copolymer (D) has a hydroxyl group as a reactive site and uses an epoxy resin in combination as a polymerizable resin. It can be activated and cured. On the other hand, since the adhesive sheet of Comparative Example 3 does not have a reactive site and does not contain a photopolymerization initiator, it is an adhesive sheet that does not undergo a curing reaction in active energy rays and post-curing. In addition, the adhesive sheet of Comparative Example 4 has a radical-reactive polymerizable resin and a photopolymerization initiator, and can be cured by the photopolymerization initiator. The adhesive sheet is extremely difficult to stick to the second adherend.

(Tensile storage modulus E 'and glass transition temperature)
The release liner was removed from the adhesive sheets obtained in the examples and comparative examples, and the adhesive sheets were bonded together to prepare a sample having a thickness of 200 μm. Using a tensile dynamic viscoelasticity measuring device (TA Instruments, RSA III), the temperature was increased at a rate of 3 ° C./minute, the measurement frequency was 1.0 Hz, and the measurement temperature range was −40 to 150 ° C. The tensile storage elastic modulus (E ′) at 25 ° C. of the adhesive layer before irradiation with active energy rays was calculated. The loss tangent was calculated, and the peak temperature of the loss tangent was taken as the glass transition temperature. The glass transition temperatures of the acrylic copolymers (A) to (D) were prepared in the same manner as in Example 1 except that only the acrylic copolymer was used. The transition temperature was measured.

Also, the release liner was removed from one of the adhesive sheets obtained in the examples and comparative examples, and ultraviolet rays were applied to the exposed adhesive layer surface using an ultraviolet electrodeless lamp (fusion lamp H bulb) at 500 mJ / cm ^2. The tensile storage elastic modulus (E ′) at 25 ° C. of the adhesive layer after irradiation with active energy rays was the same as described above except that the adhesive sheet obtained by irradiation was cut into 5 mm × 50 mm. ) Was calculated. The adhesive sheet obtained in Comparative Example 4 was irradiated with the ultraviolet rays without removing the release liner.

  Further, the test pieces obtained by irradiating the ultraviolet rays on the adhesive sheets obtained in the examples and comparative examples were further cut into 5 mm × 50 mm from cured products obtained by leaving them at 70 ° C. for 1 hour. The tensile storage elastic modulus (E ′) and glass transition temperature of the cured adhesive layer at 100 ° C. and 25 ° C. were calculated in the same manner as described above except that the obtained one was used.

(Swelling resistance and floating resistance)
After cutting the adhesive sheets obtained in the examples and comparative examples to a size of 60 mm × 60 mm, one release liner was removed, and the thickness was 0.2 mm at a speed of 1 m / min at a pressure of 0.2 MPa. A polycarbonate sheet (Sumitomo Bakelite Co., Ltd., Polycaace ECG-101) was bonded to prepare a test piece.

Next, the remaining one release liner was removed, and a test piece obtained by irradiating the exposed adhesive layer surface with ultraviolet rays at 500 mJ / cm ² using an ultraviolet electrodeless lamp (fusion lamp H bulb) was obtained. After a lapse of time, it was temporarily fixed to a 1.5 mm thick polycarbonate plate (Mitsubishi Gas Chemical Co., Ltd., Iupilon NF-200VUNS2). The adhesive sheet obtained in Comparative Example 4 was irradiated with the ultraviolet rays without removing the release liner.

Immediately after the temporary fixation, heat pasting was performed for 2 minutes at 130 ° C. and a pressure of 0.1 MPa using a hot press apparatus. As a hot press apparatus, a hot press machine “TP-750 Air Press” manufactured by Tester Sangyo Co., Ltd. was used. The surface of the obtained test piece was visually observed from the polycarbonate sheet having a thickness of 0.2 mm and evaluated based on the following criteria.
○: No swelling or lifting was observed.
(Triangle | delta): Generation | occurrence | production of swelling or floating was seen in part.
X: Swelling or floating was observed over the entire surface.

  Furthermore, each test piece obtained above was allowed to stand for 1 hour at 70 ° C. and post-cured, and then left at 85 ° C. and 85% RH for 24 hours as wet heat conditions. Was observed from the first adherend surface side and evaluated based on the same criteria as described above.

(Gel fraction)
The adhesive sheets obtained in the above examples and comparative examples were cut into a size of 40 mm × 50 mm, and then only the single-sided release liner was removed to obtain a test piece. After measuring the mass of the test piece, it was immersed in toluene adjusted to 23 ° C. for 24 hours.
After the immersion, the test piece was taken out, and the mass of what was dried in a dryer at 105 ° C. for 1 hour was measured. Based on the said mass and the following formula | equation, the gel fraction of the adhesive bond layer before active energy ray irradiation was computed.

  Gel fraction (% by mass) of adhesive layer before irradiation with active energy ray = {(mass of adhesive layer of adhesive sheet remaining without being dissolved in toluene) / (adhesive layer of adhesive sheet before immersion in toluene) Mass)} × 100

  The mass of the adhesive layer of the adhesive sheet before immersion refers to a value obtained by subtracting the mass of the release liner used for the production from the mass of the test piece. Further, the mass of the remaining adhesive layer refers to a value obtained by subtracting the mass of the release liner from the mass after the residue is dried.

The release liner was removed from one of the adhesive sheets obtained in the examples and comparative examples, and the surface of the exposed adhesive layer was irradiated with ultraviolet rays of 500 mJ / cm ² using an ultraviolet electrodeless lamp (fusion lamp H bulb). The adhesive sheet thus obtained was left to stand at 70 ° C. for 1 hour to be post-cured, and then the adhesive layer after curing was evaluated in the same manner as the evaluation of the gel fraction of the adhesive layer before irradiation with active energy rays. The gel fraction was measured. The adhesive sheet obtained in Comparative Example 4 was irradiated with the ultraviolet rays without removing the release liner.

(Total light transmittance Tt and haze)
For the total light transmittance Tt and haze, two polycarbonate sheets having a thickness of 0.2 mm, a total light transmittance Tt of 90% and a haze of 0.2% and a thickness of 0.2 mm were prepared. The test obtained by removing the release liner on one side from the adhesive sheet obtained in the example and irradiating the exposed adhesive layer surface with ultraviolet rays of 500 mJ / cm ² using an ultraviolet electrodeless lamp (fusion lamp H bulb) After the piece was bonded between the two polycarbonate sheets so as not to contain air bubbles, it was subjected to a post-curing process at 70 ° C. for 1 hour, and the total light was transmitted with an arbitrary total light transmittance meter according to JIS K7136. The transmittance Tt and haze were measured.

(Peel adhesion before active energy ray irradiation)
The adhesive sheets obtained in the examples and comparative examples were cut into a width of 20 mm and a length of 100 mm, and after removing the release liner on one side, a polyester film having a thickness of 50 μm (S-50 manufactured by Unitika Ltd.) was used. The test piece was produced by bonding. Each test piece was applied to a 1.5 mm thick polycarbonate plate (Mitsubishi Gas Chemical Co., Ltd., Iupilon NF-200VUNS2) in an environment of 23 ° C. and 50% RH, and reciprocated at a speed of 300 mm / min with a 2 kg roller. After pressurizing, the adhesive strength when the polyester film was peeled off at a pulling speed of 50 mm / min in the direction of 180 ° within 1 minute was measured. In addition, about the adhesive sheet of the comparative example 3, since it is an adhesive sheet which does not generate | occur | produce hardening reaction by an active energy ray and post-heating, only the peel adhesive force of the adhesive sheet before active energy ray irradiation, and the peel adhesive force after leaving wet heat are used. evaluated.

(Peel adhesion after irradiation with active energy rays)
In the same manner as described above, a test piece was prepared by bonding to a 50 μm thick polyester film, the release liner on the other side was removed, and an ultraviolet electrodeless lamp (fusion lamp H bulb) was used on the surface of the exposed adhesive layer. Adhesive strength was measured in the same manner as described above except that a test piece that was allowed to stand for 20 minutes after irradiation with 500 mJ / cm ^{2 of} ultraviolet rays was used. The adhesive sheet obtained in Comparative Example 4 was irradiated with the ultraviolet rays without removing the release liner.

(Peel adhesion after curing reaction)
In the same manner as described above, a test piece left for 20 minutes after ultraviolet irradiation was prepared, and temporarily fixed to the polycarbonate plate having a thickness of 1.5 mm. Immediately after the temporary fixation, heat pasting was performed for 2 minutes at 130 ° C. and a pressure of 0.1 MPa using a hot press apparatus. As the hot press device, a hot press machine “TP-750 Air Press” manufactured by Tester Sangyo Co., Ltd. was used. The obtained test piece was allowed to stand at 70 ° C. for 1 hour for post-curing, and the peel adhesive strength was measured in the same manner as described above.

(Peel adhesion after leaving wet heat)
The test piece cured in the same manner as described above was allowed to stand in 85 ° C. and 85% RH for 24 hours, taken out in 23 ° C. and 50% RH, and one hour later, peel adhesion was measured in the same manner as described above.

(Storage stability)
The adhesive sheets obtained in Examples and Comparative Examples were allowed to stand at 40 ° C. for 30 days, then the gel fraction was measured in the same manner as described above, and evaluated based on the following criteria.
○: Change in gel fraction was less than 10%.
X: The change of the gel fraction was 10 mass% or more.

Claims (12)

It is an adhesive sheet used for bonding two or more adherends having a surface that does not transmit active energy rays, and the adhesive layer is stretched and stored at 25 ° C. before irradiating the active energy rays to the surface of the adhesive layer. The elastic modulus is 1 × 10 ³ to 1 × 10 ⁶ Pa, and the tensile storage elastic modulus of the adhesive layer at 25 ° C. after irradiating the surface of the adhesive layer with active energy rays is 1 × 10 ³ to 1 × 10 ^6. The adhesive sheet which is Pa and the tensile storage elastic modulus of the adhesive bond layer at 100 ° C. after the curing reaction is 2 × 10 ⁴ Pa or more. The adhesive sheet according to claim 1, comprising at least one polymerizable resin. The adhesive sheet according to claim 1 or 2, wherein the polymerizable resin has a weight average molecular weight of 10,000 to 1,000,000. The adhesive sheet according to any one of claims 1 to 3, wherein the polymerizable resin has a glass transition temperature of -30 to 50 ° C. The adhesive sheet according to any one of claims 1 to 4, wherein the polymerizable resin contains an epoxy group and / or an oxetanyl group. The adhesive sheet according to any one of claims 1 to 5, wherein the polymerizable resin contains a group having a nitrogen atom. The adhesive sheet according to any one of claims 1 to 6, wherein the polymerizable resin is an acrylic copolymer. The adhesive sheet according to any one of claims 1 to 7, comprising at least two or more kinds of polymerizable resins. The total epoxy equivalent of the polymerizable resin is 500 to 20,000 g / eq. The adhesive sheet according to any one of claims 1 to 8. The molded article with which the adhesive sheet of any one of Claims 1-9 was bonded. The molded article according to claim 10, wherein the material is made of resin. The process [1] of bonding the adhesive layer of the adhesive sheet according to any one of claims 1 to 9 and the first adherend by pressure-sensitive adhesion without heating, the adhesive sheet A step [2] of initiating polymerization by irradiating the other surface of the adhesive layer with active energy rays, and a step [3] of applying a second adherend to the surface of the adhesive layer of the laminate by pressing. The manufacturing method which a 1st to-be-adhered body and a 2nd to-be-adhered body include in order of the process [4] which postcures the laminated body bonded by the said adhesive sheet.