JP5073400B2 - Curable resin composition with excellent heat stability - Google Patents

Description

  The present invention relates to a curable resin composition excellent in heat stability, a heat resistance stabilizing effect enhancer, and a heat resistance stability enhancing method. The curable resin composition of the present invention has excellent heat resistance, hue stability and flexibility, and is useful for applications such as adhesives, pressure-sensitive adhesives, coating agents, sealing materials, inks, sealing materials, and potting materials. .

  In recent years, along with the development of digital technology, the miniaturization and weight reduction of electrical and electronic components has progressed. Adhesives, pressure-sensitive adhesives, coating agents, sealing materials, inks, sealing materials, and potting materials used for these components have been developed. In addition, there is a demand for improvement in performance associated with downsizing and thinning. On the other hand, some of these electrical and electronic components are accompanied by heat generation, and the stress generated by the thermal expansion of the base material is relaxed by a miniaturized / thinned sealing layer, adhesive layer, etc. There is a demand for a small change in elastic modulus with respect to a long-term thermal history. Further, hue stability is also required for adhesives and coating agents for optical materials.

Examples of methods that satisfy these requirements include:
(1) An ultraviolet curable resin composition comprising a conjugated diene polymer (A) having at least one (meth) acryloyl group as an average per molecule, a (meth) acrylic monomer (B) and a photoinitiator (C) Thing (refer patent document 1);
(2) A photocurable resin composition comprising a photocurable hydrogenated polybutadiene-based resin, a reactive compound having a polymerizable terminal group, and a photopolymerization initiator (see Patent Document 2);
(3) Photopolymerizable oligomer (A), photopolymerizable monomer (B), first component photopolymerization initiator (Ca), second component photopolymerization initiator (Cb), light stabilizer (D), An ultraviolet curable molding material comprising an ultraviolet absorber (E), an antioxidant (F) and an antistatic agent (G) (see Patent Document 3);
(4) Compound (A) having one (meth) acryloyloxy group and a polyolefin skeleton and a number average molecular weight of 500 to 10,000, having two (meth) acryloyloxy groups and a hydrocarbon skeleton, and having a carbon number A photocurable resin composition comprising 25 to 200 compounds (B) and a radical photopolymerization initiator (C) (see Patent Document 4);
Etc. have been proposed.

JP 2003-192750 A Japanese Patent Laid-Open No. 1-113417 JP 2003-26715 A JP 2006-16549 A

However, although the ultraviolet curable resin composition disclosed in Patent Document 1 has flexibility, “polyisoprene having three methacryloyl groups as an average per molecule”, which is substantially useful, is intramolecular. Have a double bond, and thus there are problems such as insufficient heat resistance.
In addition, the photocurable resin composition containing the “hydrogenated polybutadiene resin” disclosed in Patent Document 2 has an elastic modulus after a long-term high-temperature treatment with respect to the “polybutadiene resin” shown in the comparative example, Although the appearance change is small and excellent, there is a problem that the manufacturing method becomes complicated because a process of hydrogenating the polybutadiene resin is required.
Furthermore, the ultraviolet curable molding material containing polybutadiene (meth) acrylate, which is substantially useful in Patent Document 3, has problems such as insufficient flexibility.
And the photocurable resin composition which has 1 (meth) acryloyloxy group and the polyolefin skeleton which are shown by patent document 4, and contains the compound (A) of number average molecular weight 500-10,000 is a comparative example. However, although the hue stability has been improved, there is a problem that it is still insufficient for market demand.

  Accordingly, an object of the present invention is to provide a flexible curable resin composition that has a small change in elastic modulus even when exposed to a high temperature for a long period of time and is excellent in hue stability in order to solve the above problems. It is in.

As a result of intensive studies to achieve the above object, the present inventors have (A) polyisoprene having a (meth) acryloyl group in the molecule, (B) a monofunctional (meth) acrylate monomer (hereinafter simply referred to as “ And ( C) a composition comprising a radical polymerization initiator and (D) a hindered amine compound having no secondary amino group in the molecule. As a result, it was found that the above-mentioned conventional problems can be solved and a curable resin composition having excellent heat resistance stability can be obtained, and the present invention has been completed.

That is, according to the present invention, the above object is
(1) (A) polyisoprene having a (meth) acryloyl group in the molecule, (B) a monofunctional (meth) acrylate monomer, (C) a radical polymerization initiator, and (D) a secondary amino group in the molecule. And a mass ratio of the polyisoprene (A) having the (meth) acryloyl group and the monofunctional (meth) acrylate monomer (B) is in the range of 1/99 to 99/1. Curing properties with excellent heat stability including 0.01 to 20 parts by mass of the radical polymerization initiator (C) and 0.01 to 10 parts by mass of the hindered amine compound (D) with respect to 100 parts by mass of the total amount of the two. This is achieved by the resin composition.

The present invention also provides:
(2) The number average molecular weight of the polyisoprene (A) having a (meth) acryloyl group is in the range of 5,000 to 200,000, and the (meth) acryl equivalent is in the range of 700 to 20,000 g / eq. The curable resin composition,
(3) The curable resin composition obtained by the esterification reaction with (meth) acrylate having a hydroxyl group after polyisoprene (A) having a (meth) acryloyl group is added with maleic anhydride to polyisoprene. And (4) a hindered amine compound (D) having no secondary amino group in the molecule is bis (1,2,2,6,6-pentamethyl-4-piperidyl) sebacate, methyl 1,2 , 2,6,6-pentamethyl-4-piperidyl sebacate, 1,2,3,4-butanetetracarboxylic acid tetrakis (1,2,2,6,6-pentamethyl-4-piperidinyl) The said curable resin composition which is at least 1 type is included as a suitable aspect.

And according to the present invention, the above object is
(5) minutes in the child using the hindered amine compound having no secondary amino groups and (D) as an active ingredient, polyisoprene having a (meth) acryloyl groups in the (A) molecules, (B) a monofunctional A method for enhancing the heat-resistant stability of a curable resin composition comprising (meth) acrylate monomer of (C) and a radical polymerization initiator,
Is also achieved.

  ADVANTAGE OF THE INVENTION According to this invention, the curable resin composition which is excellent in the hue stability after hardening and heat-resistant stability, is excellent in an elongation characteristic, has high elongation at break, and can obtain a flexible cured material is provided.

As essential components of the curable composition of the present invention, (A) a polyisoprene having a (meth) acryloyl group in the molecule (meaning a polyisoprene having an acryloyl group and / or a methacryloyl group in the molecule), B) (meth) acrylate monomer (meaning acrylate monomer and / or methacrylate monomer), (C) radical polymerization initiator and (D) hindered amine compound having no secondary amino group in the molecule are included .
First, polyisoprene having a (meth) acryloyl group in the molecule (A), which is the first component constituting the curable resin composition of the present invention (hereinafter simply referred to as polyisoprene (A) or (meth) acryloyl group). The polyisoprene (A) may be used without particular limitation as long as the effects of the present invention can be obtained, but the number average molecular weight is 5,000 to 200,000. It is preferably in the range, more preferably in the range of 8,000 to 100,000, and even more preferably in the range of 11,000 to 60,000. The number average molecular weight of the polyisoprene (A) is preferably in the range of 5,000 to 200,000 from the viewpoint of the flexibility of the cured product and the preparation workability of the curable resin composition.
In addition, the number average molecular weight in this specification means the number average molecular weight of polystyrene conversion measured by gel permeation chromatography (GPC).

The polyisoprene (A) preferably has a (meth) acryl equivalent (meaning acrylic equivalent and / or methacryl equivalent) in the range of 700 to 20,000 g / eq, 1,100 to 15, 000 g / eq is more preferable, and 2,000 to 10,000 g / eq is still more preferable. It is desirable from the viewpoint of obtaining a flexible cured product that the (meth) acryl equivalent of polyisoprene (A) is in the range of 700 g / eq to 20,000 g / eq.
In addition, the (meth) acryl equivalent in this specification means the molecular weight per (meth) acryloyl group.

  The polyisoprene used as a raw material before producing the polyisoprene (A) having a (meth) acryloyl group is produced by polymerizing isoprene. The method for producing polyisoprene is not particularly limited, and for example, an anionic polymerization method, a polymerization method using a Ziegler catalyst, or the like can be employed. In the case of the anionic polymerization method, for example, an alkali metal such as metallic sodium or metallic lithium in a solvent inert to the polymerization reaction such as hexane, cyclohexane, benzene or toluene in an inert gas atmosphere such as argon or nitrogen; methyl Alkyllithium compounds such as lithium, ethyllithium, n-butyllithium, s-butyllithium, etc. are used as initiators, usually in the range of polymerization temperature-100 ° C-100 ° C, polymerization time 0.01-200 hours. The method of polymerizing isoprene is employed.

The production method of the polyisoprene (A) having a (meth) acryloyl group is not particularly limited. For example, after adding maleic anhydride to the polyisoprene produced by the above method, the polyisoprene (A) further has a hydroxyl group (meta ) A method of esterifying with acrylate (meaning acrylate and / or methacrylate having a hydroxyl group) can be adopted as a preferred method.
The method of adding maleic anhydride is not particularly limited. For example, a method of adding maleic anhydride to polyisoprene, and further adding a radical catalyst as necessary, and heating in the presence or absence of an organic solvent. Can be mentioned.

Examples of the organic solvent used in the above method generally include hydrocarbon solvents and halogenated hydrocarbon solvents. Among these organic solvents, hydrocarbon solvents such as n-butane, n-hexane, n-heptane, cyclohexane, benzene, toluene and xylene are preferable.
Examples of the radical catalyst used in the above method include di-s-butylperoxydicarbonate, t-amylperoxypivalate, t-amylperoxy-2-ethylhexanoate, and azobisisobutyronitrile. It is done. Among these radical catalysts, azoisobutyronitrile is preferably used.

Further, the method of reacting polyisoprene added with maleic anhydride and (meth) acrylate having a hydroxyl group is not particularly limited. For example, (meth) acrylate having hydroxyl group on polyisoprene added with maleic anhydride. Further, there may be mentioned a method of adding an esterification catalyst as necessary and heating in the presence or absence of an organic solvent.
Examples of the (meth) acrylate having a hydroxyl group include 2-hydroxyethyl (meth) acrylate and 2-hydroxypropyl (meth) acrylate. These can be used alone or in combination of two or more. Among these (meth) acrylates having a hydroxyl group, 2-hydroxyethyl (meth) acrylate is preferably used.

  Examples of the organic solvent used in the method of reacting polyisoprene and (meth) acrylate having a hydroxyl group generally include hydrocarbon solvents and halogenated hydrocarbon solvents. Among these organic solvents, hydrocarbon solvents such as n-butane, n-hexane, n-heptane, cyclohexane, benzene, toluene and xylene are preferable.

  Examples of the esterification catalyst used in the above method include amine catalysts such as triethylamine, pyridine, 4-dimethylaminopyridine, 4-pyrrolidinopyridine, N, N-dimethylbenzylamine, sulfuric acid, hydrochloric acid, p-toluenesulfone. Examples include acid catalysts such as acids, and metal salt catalysts such as zinc chloride and sodium acetate. Among these esterification catalysts, amine catalysts are preferably used.

Next, the monofunctional (meth) acrylate monomer (B) as the second component constituting the curable composition of the present invention is not particularly limited as long as it can be cured by the radical polymerization initiator (C). For example, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, butylethoxy (meth) acrylate, butylethyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (Meth) acrylate, dicyclopentenyl (meth) acrylate, dicyclopentenyloxyethyl (meth) acrylate, dicyclopentanyl (meth) acrylate, cyclohexyl (meth) acrylate, isobornyl (meth) acrylate, 2-hydroxyethyl ( Meta) Acry 2-hydroxypropyl (meth) acrylate, phenoxyhydroxypropyl (meth) acrylate, morpholine (meth) acrylate, phenoxyethyl (meth) acrylate, N, N-diethylaminoethyl (meth) acrylate, N, N-dimethyl aminoethyl (meth) acrylate, glycidyl (meth) acrylate, methoxy diethylene glycol (meth) acrylate, methoxy dipropylene glycol (meth) acrylate, etc. monofunctional monomers over such nonyl phenoxy polyethylene glycol (meth) acrylate. These (meth) acrylate monomers may be used alone or in combination of two or more.

  The amount of polyisoprene (A) and (meth) acrylate monomer (B) having a (meth) acryloyl group in the molecule is the same as that of polyisoprene (A) and (meth) acrylate having a (meth) acryloyl group in the molecule. The mixing ratio of the monomer (B) is in the range of 1/99 to 99/1 as a mass ratio, preferably 5/95 to 95/5, more preferably 10/90 to 90/10. When the mixing ratio of the polyisoprene (A) having a (meth) acryloyl group in the molecule and the (meth) acrylate monomer (B) is out of 1/99 as a mass ratio, that is, the amount of the (meth) acrylate monomer (B) used When the ratio is more than 99% by mass, a flexible cured product tends to be not obtained. On the other hand, when the mixing ratio of the polyisoprene (A) having a (meth) acryloyl group in the molecule and the (meth) acrylate monomer (B) is out of 99/1 as a mass ratio, that is, the (meth) acrylate monomer (B) When the usage ratio is less than 1% by mass, the curing rate tends to be slow.

  Moreover, as the radical polymerization initiator (C) that is the third component constituting the curable composition of the present invention, for example, a radical photopolymerization initiator that generates radicals by being decomposed by active energy rays such as ultraviolet rays, Examples thereof include a thermal decomposition type radical polymerization initiator that decomposes by heating to generate radicals.

  Examples of the radical photopolymerization initiator include 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-hydroxycyclohexyl phenyl ketone, 2-methyl- [4- (methylthio) phenyl] -2- Morpholino-1-propanone, 2,2-dimethoxy-1,2-diphenylethane-1-one, 1- [4- (2-hydroxyethoxy) phenyl] -2-hydroxy-2-methyl-1-propane-1 -One, 2-hydroxy-1- {4- [4- (2-hydroxy-2-methylpropionyl) benzyl] phenyl} -2-methylpropan-1-one, 2-methyl-1- (4-methylthiophenyl) ) -2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) butanone, 2- (di Ketones such as tilamino) -2-[(4-methylphenyl) methyl] -1- [4- (4-morpholinyl) phenyl] -1-butanone, camphorquinone, benzophenone, benzoin methyl ether, benzoin ethyl ether; 2 , 4,6-trimethylbenzoyldiphenylphosphine oxide, acylphosphine oxides such as bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide; bis (η5-2,4-cyclopentadien-1-yl) bis ( Titanocenes such as 2,6-difluoro-3- (1H-pyrrol-1-yl) phenyl) titanium; 1,2-octanedione-1- [4- (phenylthio) -2- (O-benzoyloxime)] Ethanone-1- [9-ethyl-6- (2-methylbenzoyl) Oxime esters such as 9H-carbazol-3-yl] -1- (O-acetyloxime); oxyphenylacetic acid 2- [2-oxo-2-phenylacetoxyethoxy] ethyl ester, oxyphenylacetic acid 2- (2- And oxyphenylacetic acid esters such as hydroxyethoxy) ethyl ester. Of these, ketones such as 2-hydroxy-2-methyl-1-phenylpropan-1-one and 1-hydroxycyclohexyl phenyl ketone, and 2,4,6-trimethylbenzoyldiphenylphosphine oxide, bis (2, Acylphosphine oxides such as 4,6-trimethylbenzoyl) phenylphosphine oxide are preferably used.

  Examples of the thermal decomposition type radical polymerization initiator include 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate, 1,1-bis (t-butylperoxy) cyclohexane, , 1-bis (t-butylperoxy) cyclododecane, di-t-butylperoxyisophthalate, t-butylperoxybenzoate, dicumyl peroxide, t-butylcumyl peroxide, 2,5-dimethyl-2 , 5-di (t-butylperoxy) hexane, 2,5-dimethyl-2,5-di (t-butylperoxy) -3-hexyne, and cumene hydroperoxide.

  The radical polymerization initiator (C) may be used alone or in combination of two or more. The addition amount of the radical polymerization initiator (C) is 0.01 to 20 parts by mass with respect to 100 parts by mass of the total amount of the polyisoprene (A) having the (meth) acryloyl group and the (meth) acrylate monomer (B). Preferably, it is 0.05-15 mass parts, More preferably, it is 0.1-10 mass parts, More preferably, it is the range of 0.5-8 mass parts. When the addition amount of the radical initiator (C) is less than 0.01 parts by mass, the curing rate decreases, and when it exceeds 20 parts by mass, the mechanical properties of the obtained cured product tend to decrease.

  It is important that the hindered amine compound (D), which is the fourth component constituting the curable composition of the present invention, does not have a secondary amino group in the molecule. When a hindered amine compound having a secondary amino group in the molecule is used, the hue stability and heat stability of the cured product are inferior.

  Examples of the hindered amine compound (D) having no secondary amino group in the molecule used in the present invention include bis (2,2,6,6-tetramethyl-1- (octyloxy) -decanedioate. 4-piperidinyl) ester, bis (1,2,2,6,6-pentamethyl-4-4piperidyl) [[3,5-bis (1,1-dimethylethyl) -4-hydroxyphenyl] methyl] butylmalo Bis (1,2,2,6,6-pentamethyl-4-piperidyl) sebacate, methyl 1,2,2,6,6-pentamethyl-4-piperidyl sebacate, 1,2,3,4-butane And tetracarboxylic acid tetrakis (1,2,2,6,6-pentamethyl-4-piperidinyl), 1,2,2,6,6-pentamethyl-4-piperidyl methacrylate, and the like. Among them, bis (1,2,2,6,6-pentamethyl-4-piperidyl) sebacate, methyl 1,2,2,6,6-pentamethyl-4-piperidyl sebacate, 1,2,3,4-butane Tetracarboxylic acid tetrakis (1,2,2,6,6-pentamethyl-4-piperidinyl) is preferably used. In addition, as the hindered amine compound (D) used in the present invention, a hindered amine light stabilizer having no secondary amino group in the molecule can be used. For example, commercially available “TINUVIN 765”, “TINUVIN” "292", "TINUVIN 622LD" (trade name, manufactured by Ciba Specialty Chemicals); "ADK STAB LA-52", "ADK STAB LA-62", "ADK STAB LA-63P", "ADK STAB LA-82" (product) Name, manufactured by ADEKA Corporation) is preferably used.

  These hindered amine compounds (D) may be used alone or in combination of two or more. The added amount of the hindered amine compound (D) is 0.01 to 10 parts by mass with respect to 100 parts by mass of the total amount of the polyisoprene (A) having a (meth) acryloyl group and the (meth) acrylate monomer (B). The range is preferably 0.02 to 5 parts by mass, more preferably 0.04 to 3 parts by mass, still more preferably 0.05 to 2.5 parts by mass, and most preferably 0.1 to 1 part by mass. Range. When the addition amount of the hindered amine compound (D) is less than 0.01 parts by mass, the heat resistance is deteriorated, and when it exceeds 10 parts by mass, the mechanical properties of the obtained cured product tend to be lowered.

In addition, the present invention provides a heat resistance stabilizing effect enhancer containing a hindered amine compound (D) having no secondary amino group in the molecule as an active ingredient, (A) a (meth) acryloyl group in the molecule. The same effect can be obtained by blending with a curable resin composition comprising polyisoprene having, (B) (meth) acrylate monomer and (C) radical polymerization initiator. (D) The heat-resistant stability enhancer containing as an active ingredient a hindered amine compound having no secondary amino group in the molecule is not particularly limited as long as the effect of the present invention is exhibited. The hindered amine light stabilizer which does not have a secondary amino group in the molecule can be exemplified. The heat-resistant stabilizing effect enhancer comprises (A) a curable resin composition comprising a polyisoprene having a (meth) acryloyl group in the molecule, (B) a (meth) acrylate monomer, and (C) a radical polymerization initiator ( It has a secondary amino group in the molecule contained in the heat-resistant stability enhancing agent with respect to 100 parts by mass of the total amount of polyisoprene (A) and (meth) acrylate monomer (B) having a (meth) acryloyl group. It is effective when the amount of hindered amine compound (D) added is in the range of 0.01 to 10 parts by mass, preferably 0.02 to 5 parts by mass, more preferably 0.04 to 3 parts by mass, More preferably, it is the range of 0.05-2.5 mass parts, Most preferably, it is the range of 0.1-1 mass part.
The curable resin composition of the present invention or the curable resin composition has a curing accelerator, a tackifier, a plasticizer, an anti-aging agent, an ultraviolet absorber, a softener, and an antifoaming agent as long as the characteristics are not impaired. Pigments, dyes, organic fillers, fragrances and the like can be blended.

The method for preparing the curable resin composition of the present invention is not particularly limited. For example, polyisoprene (A) having a (meth) acryloyl group in the molecule, (meth) acrylate monomer (B), radical polymerization initiator (C) and a hindered amine compound (D) having no secondary amino group in the molecule, and if necessary, additives and the like are mixed at room temperature using ordinary mixing means such as a stirrer or a kneader. Can be prepared.
In addition, the curable resin composition of the present invention comprises a polyisoprene (A) having a (meth) acryloyl group in the molecule, a (meth) acrylate monomer (B), a radical polymerization initiator (C) and a second in the molecule. Heat resistant stability enhancing agent containing hindered amine compound (D) having no secondary amino group as an active ingredient, and if necessary, additives and the like are mixed at room temperature using ordinary mixing means such as a stirrer or kneader Can also be prepared.

The curable resin composition of the present invention can usually be cured by active energy rays and / or heat, but preferably is irradiated with active energy rays and, if necessary, heat is applied during or after curing. It can be cured by adding.
Examples of active energy rays include particle rays, electromagnetic waves, and combinations thereof. Examples of the particle beam include an electron beam (EB) and an α ray, and examples of the electromagnetic wave include an ultraviolet ray (UV), a visible ray, an infrared ray, a γ ray, and an X ray. Among these, electron beam (EB) or ultraviolet light (UV) is preferably used.
The active energy ray can be irradiated using a known apparatus. For example, the acceleration voltage in the case of an electron beam (EB) is suitably in the range of 0.1 to 10 MeV and the irradiation dose is in the range of 1 to 500 kGy. In the case of ultraviolet rays (UV), for example, a lamp having a radiation wavelength of 200 nm to 450 nm can be suitably used as the radiation source. In the case of an electron beam (EB), for example, a tungsten filament is used as the radiation source, and in the case of ultraviolet (UV), a low pressure mercury lamp, a high pressure mercury lamp, an ultrahigh pressure mercury lamp, a halogen lamp, an excimer lamp, a carbon arc lamp, xenon. Examples thereof include lamps, zirconium lamps, fluorescent lamps, and ultraviolet rays contained in natural light. In addition, although the irradiation time to the curable resin composition of an active energy ray changes also with the magnitude | sizes of energy, it is the range of about 0.5 to 300 second in general.

  The curable resin composition of the present invention provides a flexible cured product having a low tensile elastic modulus and is excellent in heat resistance and hue stability, so that cracking and peeling of the cured product are reduced, and an adhesive and a pressure-sensitive adhesive. (Adhesives and pressure-sensitive adhesives are sometimes referred to as adhesives), coating agents, sealing materials, inks, and the like. Applications of adhesives include, for example, bonding of optical discs such as digital versatile discs (DVD), bonding of optical films used in flat panel displays such as liquid crystal displays and plasma displays, cameras and DVDs, and compacts. For holding optical wafers used in optical heads for disk (CD) playback, for bonding optical members such as optical fibers, for bonding precision components such as semiconductors and printed wiring boards, and for dicing processes in semiconductor manufacturing The use as a dicing tape is mentioned. Applications of the coating agent include, for example, automotive headlamp coating applications and optical fiber coating applications. Examples of the use of the sealing material include a sealing material application for precision parts such as liquid crystal display elements and semiconductors. Examples of ink applications include resist ink used in the manufacture of semiconductors and printed wiring boards, aluminum foil paper, polyethylene coated paper, vinyl chloride sheets, polyester sheets, polypropylene sheets, food cans, beverage cans, etc. The use of the printing ink used for printing is mentioned.

  Moreover, the method for enhancing the heat-resistant stability effect of the present invention comprises (D) a polyisoprene having a (meth) acryloyl group in the molecule, using a hindered amine compound having no secondary amino group in the molecule, (B) A method for enhancing the heat-resistant stability of a curable resin composition comprising a (meth) acrylate monomer and (C) a radical polymerization initiator, and (D) a hindered amine compound having no secondary amino group in the molecule. As described above, by using as an active ingredient, (A) a curable composition comprising a polyisoprene having a (meth) acryloyl group in the molecule, (B) a (meth) acrylate monomer, and (C) a radical polymerization initiator. The heat stability stabilizing effect of the resin composition can be enhanced, and the same effect as the curable resin composition of the present invention is exhibited.

  EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited to this Example at all. In addition, the measurement of the polymer obtained in each Example and the comparative example and the physical-property evaluation of the curable resin composition were performed as follows.

(1) Measurement of number average molecular weight GPC-8020 manufactured by Tosoh Corporation was used, and the concentration was measured by adjusting the concentration of sample / THF = 5 mg / 10 mL. As a developing solution, THF manufactured by Wako Pure Chemical Industries, Ltd. was used.

(2) Measurement of (meth) acryloyl group 1H-NMR (500 MHz) manufactured by JEOL Ltd. was used, and measurement was performed at a concentration of sample / heavy chloroform = 100 mg / 1 mL, 512 times of integration, and a measurement temperature of 50 degrees.

(3) Compatibility The uniformity of the curable resin compositions obtained in the following examples and comparative examples was visually observed and evaluated.
○: Good compatibility (uniform)
Δ: Turbidity ×: Phase separation occurs

(4) Transparency of cured product The curable resin compositions obtained in the following Examples and Comparative Examples were injected into a 0.8 mm thick mold and the composition surface was covered with a 50 μm thick PET film. After that, using a UV irradiation device (manufactured by GS Yuasa Corporation, using HAK125L-F as a mercury lamp), an illuminance of 75 mW / cm ² and a conveyor speed of 1 m / min were set, and 700 mJ / cm in one operation. ² UV was irradiated. This was repeated 4 times to obtain a cured product. After peeling the PET film from the cured product, the transparency was evaluated by visual observation.
○: Good transparency △: Turbidity ×: No transparency

(5) Heat resistance test (hue stability test)
The cured product obtained by removing the PET film in (4) above was allowed to stand in an atmosphere at 25 ° C. for 24 hours, and a strip-shaped test piece having a length of 60 mm × width of 6 mm × thickness of 0.8 mm was produced. Next, the prepared test piece is left in a gear oven at 100 ° C. for 72 hours, 240 hours, and 480 hours, and the hue change in each test piece is visually checked together with the test piece before heat treatment (displayed in 0 hours). confirmed.
◎: Colorless ○: Pale yellow △: Yellow ×: Brown

(6) Heat resistance test (tensile test)
The test piece produced in the above (5) was subjected to a tensile test at a tensile speed of 50 mm / min, and the breaking strength, breaking elongation, and tensile modulus before and after the heat treatment were measured.

Below, the detail of each component used by the Example and the comparative example is described.
(A) Polyisoprene Reference Example 1 having a (meth) acryloyl group in the molecule
<1> 245 g of hexane and 0.8 g of sec-butyllithium were charged in a 1 liter autoclave that had been purged with nitrogen, then heated to 50 ° C., 300 g of isoprene were added, and polymerization was carried out for 2 hours. . The obtained polymerization solution was poured into methanol, the polymer was reprecipitated and filtered, and vacuum dried at 80 ° C. for 10 hours to obtain 300 g of polyisoprene. When a part of the sample was analyzed by GPC, the number average molecular weight (Mn) in terms of polystyrene was 36,000, and the molecular weight distribution (Mw / Mn) was 1.04.
<2> Charge 300 g of the polyisoprene obtained in <1> above into a 1 liter autoclave that has been purged with nitrogen, add 4.5 g of maleic anhydride, and react at 160 ° C. for 20 hours to give polyisoprene. Maleic anhydride was added. Next, 6.3 g of 2-hydroxyethyl methacrylate, 0.15 g of hydroquinone, and 0.9 g of N, N-dimethylbenzylamine were added and reacted at 80 ° C. for 6 hours to obtain polyisoprene having a methacryloyl group in the molecule (hereinafter referred to as “the polyisoprene”). And abbreviated as M-IR-1. When obtained M-IR-1 was analyzed by GPC, it was Mn = 36,800 and Mw / Mn = 1.06. Moreover, when analyzed by NMR, the (meth) acryl equivalent of M-IR-1 was 6,700 g / eq.

(B) (Meth) acrylate monomer B-1: Hitachi Chemical Co., Ltd., trade name “Fancryl FA-513A” (dicyclopentanyl acrylate)
B-2: Osaka Organic Chemical Industries, Ltd., trade name “IBXA” (isobornyl acrylate)

(C) radical polymerization initiator C-1: manufactured by Ciba Specialty Chemicals Co., Ltd., trade name “DAROCUR 1173” (2-hydroxy-2-methyl-1-phenylpropan-1-one)

(D) A hindered amine compound D-1 having no secondary amino group in the molecule D-1 manufactured by Ciba Specialty Chemicals Co., Ltd., trade name “TINUVIN 765” (bis (1,2,2,6,6- (Pentamethyl-4-piperidyl) sebacate and methyl 1,2,2,6,6-pentamethyl-4-piperidyl sebacate)
D-2: manufactured by ADEKA Corporation, trade name “ADK STAB LA-52” (1,2,3,4-butanetetracarboxylic acid tetrakis (1,2,2,6,6-pentamethyl-4-piperidinyl)

Examples 1-3
Polyisoprene (M-IR-1) having a methacryloyl group obtained in Reference Example 1, (meth) acrylate monomer (B-1 or B-2), radical polymerization initiator (C-1) and hindered amine compound ( A curable resin composition was prepared by charging D-1 or D-2) into a stainless steel 300 mL container according to the formulation shown in Table 1 and mixing for 20 minutes at room temperature using a stirring blade. The results of evaluating the obtained curable resin composition by the above method are also shown in Table 1.

Comparative Examples 1-4
Instead of the hindered amine compound (D-1) used in Example 1, a curable resin composition was obtained and evaluated in the same manner as in Example 1 except that the following heat stabilizer was used. The obtained results are also shown in Table 2.

Thermal stabilizer 1: Ciba Specialty Chemicals Co., Ltd., trade name “IRGANOX 1076” (octadecyl-3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate)
Heat stabilizer 2: Product name “IRGANOX 1726” (4,6-bis (dodecylthiomethyl) -o-cresol) manufactured by Ciba Specialty Chemicals Co., Ltd.
Thermal stabilizer 3: Ciba Specialty Chemicals, trade name “IRGASTAB FS 301 FF” (mixture of N, N-octadecylhydroxylamine and tris (2,4-di-tert-butylphenyl) phosphite)
Thermal stabilizer 4: manufactured by Sumitomo Chemical Co., Ltd., trade name “Sumilizer GS” (2- [1- (2-hydroxy-3,5-di-tert-pentylphenyl) ethyl] -4,6-di-tert- Pentylphenyl acrylate)
Thermal stabilizer 5: manufactured by Sumitomo Chemical Co., Ltd., trade name “Sumilizer TP-D” (pentaerythrityltetrakis (3-laurylthiopropionate))

Comparative Example 5
A curable resin composition was obtained and evaluated in the same manner as in Example 1 except that the blending amount of the hindered amine compound (D-1) used in Example 1 was lower than the range specified in the present invention. It was. The obtained results are also shown in Table 2.

Comparative Example 6
Instead of the hindered amine compound (D-1) used in Example 1, a hindered amine compound having a secondary amino group in the molecule (manufactured by ADEKA Corporation, trade name “ADK STAB LA-77” (bis (2, A curable resin composition was obtained and evaluated in the same manner as in Example 1 except that 2,6,6-tetramethyl-4-piperidyl) sebacate)) was used. The obtained results are also shown in Table 2.

Comparative Examples 7 and 8
A curable resin composition was used in the same manner as in Example 1 except that the following (meth) acryloyl group-containing polybutadiene was used instead of the polyisoprene (M-IR-1) having a methacryloyl group used in Example 1. And evaluated. The obtained results are also shown in Table 2.
(Meth) acryloyl group-containing polybutadiene 1: manufactured by Nippon Soda Co., Ltd., trade name “TEA-1000”
(Meth) acryloyl group-containing polybutadiene 2: manufactured by Osaka Organic Chemical Industry Co., Ltd., trade name “BAC-45”

  From the results shown in Table 1, the curable resin composition of the present invention contains a hindered amine compound that does not have a secondary amino group in the molecule, so that even after a heat test at 100 ° C. for 480 hours, It can be seen that a flexible cured product having a small change and a small change in breaking strength, breaking elongation, and tensile modulus can be obtained, and the heat resistance stability can be remarkably improved.

  On the other hand, from the results shown in Table 2, Comparative Example 1 using a typical hindered phenolic antioxidant having a primary antioxidant action, having a thioether bond in the molecule, and having both primary and secondary antioxidant actions Comparative Example 2 using a hindered phenolic antioxidant (a hue change is severe after 240 hours, not evaluated later), a hindered phenolic antioxidant excellent in coloring resistance and having a primary antioxidant action Comparative Example 4 using a thioether-based heat-resistant stabilizer having secondary antioxidant action (a hue change is severe after 240 hours, and is not evaluated thereafter), secondary in the molecule in an amount less than that of the present invention Comparative Example 5 using a hindered amine-based compound having no amino group (a hue change is severe after 72 hours and is not evaluated thereafter), and a structure different from that of the present invention Ndadoamin based compound after Comparative Example 6 heat resistance test was used hue, breaking strength, breaking elongation, large change in tensile modulus, it can be seen the heat resistance is insufficient.

In Comparative Example 3 using a blend of a hydroxylamine-based processing heat stabilizer and a phosphorus-based processing stabilizer, the compatibility was poor and a good cured product could not be obtained. For this reason, a transparency test, a hue stability test, a heat resistance test, etc. could not be evaluated.
Furthermore, in Comparative Example 7 using (meth) acryloyl group-containing polybutadiene, it was not possible to obtain a flexible cured product having a high tensile elastic modulus before the heat resistance test.
In Comparative Example 8, a relatively soft cured product was obtained using (meth) acryloyl group-containing polybutadiene, but the hue change after the heat test was large, and the breaking strength, breaking elongation, and tensile modulus were increased. It can be seen that changes greatly and the physical properties deteriorate.

  The curable resin composition of the present invention provides a flexible cured product having a low tensile elastic modulus and is excellent in heat resistance and hue stability, so that it can be used for adhesives, pressure-sensitive adhesives, coating agents, sealing materials, inks, etc. It can use suitably for a use.

Claims (5)

(A) polyisoprene having a (meth) acryloyl group in the molecule, (B) a monofunctional (meth) acrylate monomer, (C) a radical polymerization initiator, and (D) a secondary amino group in the molecule The hindered amine compound, the mass ratio of the polyisoprene (A) having the (meth) acryloyl group and the monofunctional (meth) acrylate monomer (B) is in the range of 1/99 to 99/1, It was excellent in heat stability, characterized by containing 0.01 to 20 parts by mass of a radical polymerization initiator (C) and 0.01 to 10 parts by mass of a hindered amine compound (D) with respect to 100 parts by mass of Curable resin composition.  The number average molecular weight of the polyisoprene (A) having a (meth) acryloyl group is in the range of 5,000 to 200,000, and the (meth) acryl equivalent is in the range of 700 to 20,000 g / eq. The curable resin composition having excellent heat stability according to claim 1.  2. The polyisoprene (A) having a (meth) acryloyl group is obtained by an esterification reaction with a (meth) acrylate having a hydroxyl group after adding maleic anhydride to the polyisoprene. Or the curable resin composition excellent in heat-resistant stability of 2.  The hindered amine compound (D) having no secondary amino group in the molecule is bis (1,2,2,6,6-pentamethyl-4-piperidyl) sebacate, methyl 1,2,2,6,6. -Pentamethyl-4-piperidyl sebacate and at least one selected from the group of 1,2,3,4-butanetetracarboxylic acid tetrakis (1,2,2,6,6-pentamethyl-4-piperidinyl) The curable resin composition excellent in heat-resistant stability in any one of Claims 1-3 characterized by these. (A) a polyisoprene having a (meth) acryloyl group in the molecule, (B) a monofunctional (meth) acrylate monomer, and a hindered amine compound (D) having no secondary amino group in the molecule (C) A method for enhancing the heat-resistant stability of a curable resin composition comprising a radical polymerization initiator.