JPH07150054A - Method for preventing shrinkage in curing of free radical-curing resin and its strength deterioration - Google Patents

Abstract

PURPOSE:To provide a method for preventing shrinkage in curing of a free radical-curing resin and the strength deterioration of the cured resin by adding a specific amount of a specific polyorganosiloxane. CONSTITUTION:To (A) 100wt.pt. of a free radical-curing resin, (B) 1-300wt.pt. of a polyorganosiloxane consisting of (i) a siloxane unit selected from formulae X<1>X<2>SiO, R<1>X<3>SiO and the formula I (Each of X<1> to X<4> is an organic group having C atom directly bonded to Si atom and also an alpha,beta-unsaturation), and (ii) a siloxane unit selected from a formula R<2>R<3>SiO, the formula II and SiO2, and also having a ratio of the units (i)/(ii) of 1/99-30/70 (mole%), is added. As the component (B) it is preferable to use as genuinely spherical particles with a mean diameter of 0.3-10mum consisting of a cross-linked polysiloxane containing 15mole% or more of the siloxane units selected from the formula I, the formula II and SiO2 in the total siloxane units.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of preventing shrinkage of a radical curable resin during curing and reduction of strength of the resulting cured product. Unsaturated polyester resins, unsaturated urethane resins and the like are known as radical curable resins, and cured products obtained from these radical curable resins are widely used as polymeric materials. These polymeric materials are required to have a surface appearance free of defects such as warpage, cracks and irregularities due to curing shrinkage, and desired strength and physical properties. The present invention relates to a method of curing shrinkage of a radical curable resin and a method of preventing reduction in strength of a cured product thereof, which meets such demands.

[0002]

2. Description of the Related Art Conventionally, as means for preventing cure shrinkage of a radical curable resin, 1) a radical curable resin is made to contain a soluble thermoplastic polymer, and the thermoplastic polymer is made into a fine shape during curing. Means for preventing cure shrinkage by utilizing the thermal expansion of phase-separated thermoplastic polymer by phase separation to form microdomains (26th Annual Technica
Conference SPI 12F 1971), 2) means for incorporating fine particles of a crosslinked polymer insoluble in a radical curable resin (Japanese Patent Laid-Open No. 48-81984), and 3) means for incorporating inorganic fine particles.

However, in the conventional means of 1), a) there is a large influence of the curing temperature, the curing speed, etc. in forming the microdomains by phase-separating the thermoplastic polymer, and it is necessary to set appropriate conditions. It is extremely complicated, and its effect is not uniform depending on the type of the radical-curable resin b), so that there is a drawback that the range of application is restricted. The conventional means of 2) has a drawback that the effect of preventing the curing shrinkage of c) is generally low. In particular, the conventional means of 1) and 2) include d)
There is a drawback that a decrease in hot strength of the cured product cannot be avoided. The conventional means of 3) has a drawback that e) strength properties such as bending and tensile strength of the cured product are likely to be deteriorated as a whole. Coating with a surface treatment agent for the purpose of improving such strength reduction, introduction of a reactive group onto the surface using a reactive treatment agent, for example, a silane coupling agent, and the like have been carried out. Is extremely complicated, and the desired effect cannot be obtained depending on the type of the inorganic fine particles.

[0004]

The problems to be solved by the present invention are the disadvantages of a) to e) in the conventional means of 1) to 3) described above.

[0005]

However, as a result of intensive studies to solve the above problems, the present inventors have found that a specific polyorganosiloxane modified with an organic group having an α, β-ethylenically unsaturated group. It has been found out that it is correct and suitable to contain the above in a predetermined ratio with respect to the radical curable resin.

That is, according to the present invention, in curing a radical curable resin, 1 to 300 parts by weight of the following polyorganosiloxane is added to 100 parts by weight of the radical curable resin. The present invention relates to a method for preventing shrinkage upon curing and strength reduction of the cured product.

Polyorganosiloxane: One or more siloxane units selected from the following Group A and the following B:
A poly that is mainly composed of one or more kinds of siloxane units selected from the group and has a ratio of siloxane units of group A / siloxane units of group B = 1/99 to 30/70 (mol%). Organosiloxane

Group A: siloxane unit represented by the following formula 1, siloxane unit represented by formula 2 and siloxane unit represented by formula 3 Group B: siloxane unit represented by formula 4 below, siloxane represented by formula 5 Units and siloxane units represented by Formula 6

[0009]

[Formula 1]

[Formula 2]

[Formula 3]

[Formula 4]

[Formula 5]

[Formula 6]

In the formulas 1 to 6, X ^{1 to} X ⁴ are organic groups R ^{1 to} R ⁴ having a carbon atom directly connected to the silicon atom and having an α, β-ethylenically unsaturated group. Non-radical-polymerizable, substituted or unsubstituted hydrocarbon group having a carbon atom directly bonded to the atom

The polyorganosiloxane used in the present invention is a polyorganosiloxane modified with an organic group having an α, β-ethylenically unsaturated group, that is, a radically polymerizable organic group. The siloxane unit of group A includes a siloxane unit represented by formula 1, a siloxane unit represented by formula 2, and a siloxane unit represented by formula 3. Formula 1, Formula 2
And in the formula 3, X ^{1 to} X ⁴ are organic groups having a carbon atom directly bonded to a silicon atom and having an α, β-ethylenically unsaturated group. The α, β-ethylenically unsaturated group includes a methacryloyl group, an acryloyl group, a vinyl group, an aryl group, a metaaryl group and the like. Examples of the organic group having an α, β-ethylenically unsaturated group include 1) (meth) acryloyloxyalkyl groups such as acryloyloxypropyl group, methacryloyloxyethyl group and methacryloyloxy-2-methylethyl group, and 2) vinyl. Groups, aryl groups, α, β-ethylenically unsaturated hydrocarbon groups such as metaaryl groups, 3) vinyloxypropyl groups,
Examples thereof include vinyloxyalkyl groups such as vinyloxy-2-methylethyl group, and among them, (meth) acryloyloxypropyl group, vinyl group and (meth) aryl group are advantageously selected.

In the formula 2, R ¹ is a non-radical-polymerizable, substituted or unsubstituted hydrocarbon group having a carbon atom directly bonded to a silicon atom. Examples of such an unsubstituted hydrocarbon group include an alkyl group, a cycloalkyl group, an aromatic hydrocarbon group and the like. Among them, an alkyl group such as a methyl group and an ethyl group, or a phenyl group is advantageously selected. Examples of the substituted hydrocarbon group include substituted hydrocarbon groups having an epoxy group, a cyano group, a carbamide group, an amino group or the like as a substituent, and among them, a γ-glycidoxy group and a β-glycidoxy group.
Hydrocarbon group having an epoxy group as a substituent such as (3,4-epoxy) cyclohexylethyl group, ureidopropyl group, aminopropyl group, N, N-dimethylaminopropyl group, N- (aminopropyl) aminopropyl group, etc. Is advantageously selected. The siloxane unit represented by the formula 2 may have an arbitrary ratio of a siloxane unit having an unsubstituted hydrocarbon group and a siloxane unit having a substituted hydrocarbon group.

The siloxane unit of Group B includes a siloxane unit represented by formula 4, a siloxane unit represented by formula 5, and a siloxane unit represented by formula 6. In Formula 4 and Formula 5, R ^{2 to} R ⁴ can be appropriately selected from those described above for R ¹ in Formula 2, but those that can be advantageously selected are the same as those for R ¹ .

The polyorganosiloxane used in the present invention is mainly composed of one or more siloxane units selected from Group A and one or more siloxane units selected from Group B, and A Group siloxane units / B
Group siloxane units = 1/99 to 30/70 (mol%)
It has a ratio of.

The siloxane unit constituting the main chain of the polyorganosiloxane is represented by the formula 1 and //
Alternatively, a linear polyorganosiloxane is composed of the siloxane unit represented by the formula 2 and the siloxane unit represented by the formula 4.

As the siloxane unit constituting the main chain of the polyorganosiloxane, at least one siloxane unit selected from the siloxane unit represented by the formula 3, the siloxane unit represented by the formula 5, and the siloxane unit represented by the formula 6 is used. What has is a crosslinked polyorganosiloxane.

As the polyorganosiloxane used in the present invention, one or more siloxane units selected from the siloxane unit represented by the formula 3, the siloxane unit represented by the formula 5 and the siloxane unit represented by the formula 6 are added in total. A crosslinked polyorganosiloxane having an amount of 15 mol% or more in all siloxane units is preferable. Among the crosslinked polyorganosiloxanes having such a composition ratio of siloxane units, those exhibiting the form of particles can be advantageously used. The present invention does not particularly limit the shape and size of the particles of the crosslinked polyorganosiloxane, but particles having an average particle diameter of 0.1 to 50 μm are preferable, and particles having an average particle diameter of 0.3 to 10 μm are almost the same. Spherical particles exhibiting a true sphere are particularly preferred.

The polyorganosiloxane used in the present invention can be produced by a known bulk polymerization method or aqueous suspension polymerization method using a compound capable of forming a silanol group by hydrolysis as a starting material. An aqueous suspension polymerization method is preferred for obtaining spherical particles having a morphology, particularly the above-mentioned nearly spherical shape, and as the aqueous suspension polymerization method, the method disclosed in JP-A-4-29631 can be applied.

The polyorganosiloxane used in the present invention is mainly composed of one or more siloxane units selected from the group A and one or more siloxane units selected from the group B. Including those in which various silyl groups are introduced at the chain ends. As such a silyl group,
1) Trialkylsilyl groups such as trimethylsilyl group and triethylsilyl group, 2) Alkylsilyl groups having substituents such as glycidoxypropyl / dimethylsilyl group and ureidopropyl / dimethylsilyl group, 3) Methacryloyloxypropyl / dimethylsilyl group Examples thereof include a silyl group having an α, β-ethylenically unsaturated group such as a vinyl group and a vinyl / dimethylsilyl group. Among them, a trialkylsilyl group can be advantageously selected. The introduction of the silyl group as described above to the terminal of the main chain is convenient for controlling the molecular weight of the polyorganosiloxane during production. The introduction ratio of such terminal silyl groups is usually 1 mol% or less based on all siloxane units.

In curing the radical-curable resin, the present invention contains the above-mentioned polyorganosiloxane to prevent the shrinkage of the radical-curable resin upon curing and the reduction in strength of the resulting cured product. In the present invention, the content of the polyorganosiloxane is 1 to 300 parts by weight with respect to 100 parts by weight of the radical curable resin.
It is preferably about 250 parts by weight. The polyorganosiloxane can contain 1 type (s) or 2 or more types.
When spherical particles are used as the polyorganosiloxane,
It is preferable to use two types of spherical particles having different average particle sizes, and it is more preferable to use one having a ratio of the average particle sizes of the two types of spherical particles of 3 times or more.

The present invention does not particularly limit the type of radical curable resin used. Radical curable resin
As an ethylenically unsaturated monomer component, 1) an unsaturated polyester obtained from α, β-unsaturated dicarboxylic acid and glycols, 2) an epoxy resin obtained from bisphenols and epichlorohydrin, and (meth) acrylic acid Ester which is a reaction product of 3), unsaturated urethane obtained by urethanization reaction of polyisocyanate and hydroxyalkyl (meth) acrylate, 4)
Unsaturated oligourethanes obtained by urethane reaction with polyisocyanate, polyol and hydroxyalkyl (meth) acrylate, 5) unsaturated oligoesters obtained by esterification reaction with polyol, polycarboxylic acid or (meth) acrylic acid, etc. And is usually diluted to an appropriate concentration with a vinyl monomer copolymerizable with these, for example, styrene, divinylbenzene, methyl methacrylate and the like.

In the present invention, the method for curing the radical-curable resin is as follows: 1) radical-curing using a radical polymerization initiator at room temperature or under heating, 2)
There is a method of photocuring in the presence of a photopolymerization initiator using energy rays such as ultraviolet rays and electron rays. A known method using a radical polymerization initiator can be applied to the radical curing of 1). Radical polymerization initiators include dibenzoyl peroxide, t-butylperoxy-2-ethylhexanoate, t-butylperoxybenzoate, 1,1-di-
Examples thereof include t-butylperoxy-3,3,5-trimethylcyclohexane and bis (4-t-butylcyclohexyl) peroxydicarbonate, and these may be used alone or in combination of two or more. In addition to the radical polymerization initiator, N, N-dimethyl-p-toluidine,
Aromatic tertiary amines such as N, N-dimethylaniline and cobalt salts such as cobalt octenoate and cobalt naphthenate can be used as the curing accelerator.

A publicly known method using a photopolymerization initiator and energy rays can be applied to the photocuring of the above 2). Examples of the photopolymerization initiator include 1) carbonyl compounds such as benzoin, α-methylbenzoin, anthraquinone, chloranthraquinone and acetophenone, 2) sulfur compounds such as diphenylsulfide, diphenyldisulfide and dithiodicarbamate, and 3) α-chloromethylnaphthalene. ,
Examples thereof include polycyclic aromatic compounds such as anthracene. The use ratio of these photopolymerization initiators to the radical curable resin is not particularly limited, but usually the radical curable resin 10
The amount of the photopolymerization initiator is 0.1 to 10 parts by weight with respect to 0 parts by weight. A photosensitizer such as n-butylamine, triethanolamine, N, N-dimethylaminobenzenesulfonic acid diallylamide, or N, N-dimethylaminoethyl methacrylate can be used together with the photopolymerization initiator. Examples of energy rays include visible rays, ultraviolet rays, and electron rays, but ultraviolet rays can be advantageously applied.

The method of the present invention is most effective when applied to optical three-dimensional modeling by photocuring.
A photocured product having excellent physical properties can be obtained. For application to such optical three-dimensional modeling, it is preferable to use unsaturated urethane disclosed in JP-A-4-72353 and JP-A-4-314715 as the ethylenically unsaturated monomer component of the radical curable resin.

Various methods are known as optical three-dimensional molding methods (Japanese Patent Laid-Open Nos. 56-144478 and 60-60).
247514, JP-A-1-204915, JP-A-3-4
1126), for example, an operation of forming a cured layer first, then supplying an uncured composition on the cured layer, and irradiating the composition with an energy ray to form the next cured layer. There is a method in which a desired cured model is formed by repeating the process, and post-curing is further performed if necessary.

[0026]

【Example】

Test Category 1 (Synthesis of Polyorganosiloxane) Polyorganosiloxanes a to e, r-1 and r-2 were synthesized as follows. The contents are shown in Table 1. -Synthesis of polyorganosiloxane a 658 ml of water and 8.3 g of 28% ammonia water in a flask.
6.4 g of ethyl orthosilicate (0.
031 mol), octamethylcyclotetrasiloxane 2
A mixture of 4.7 g (0.084 mol), methyltrimethoxysilane 75.4 g (0.553 mol) and γ-methacryloxypropyltrimethoxysilane 19.8 g (0.08 mol) was added dropwise over 1 hour. Polycondensation was carried out while hydrolyzing at the solution interface in a two-layer state. As the reaction proceeded, the product gradually settled into the lower layer and the lower layer became cloudy,
In about 2 hours, the two-layer state disappeared and a homogeneous system was formed. After stirring at room temperature for 2 hours and then at 60 ° C. for 3 hours,
After cooling to room temperature, the produced white fine particles were filtered off. Then, the white fine particles were washed and dried to obtain 78.3 g of polyorganosiloxane a. The polyorganosiloxane a obtained here was an almost spherical fine particle having an average particle diameter of 1.0 μm and a ratio of major axis to minor axis of 1.04.

Synthesis of polyorganosiloxane b As with polyorganosiloxane a, water 658 m
l, 28% ammonia water 8.3 g, ethyl orthosilicate 83.4 g (0.40 mol), methyltrimethoxysilane 70.2 g (0.515 mol), glycidoxypropylmethyldimethoxysilane 5.5 g (0. (025 mol), γ-methacryloxypropyltrimethoxysilane (12.4 g (0.05 mol)) and trimethylmethoxysilane (1.0 g (0.01 mol)) were used to carry out hydrolysis and polycondensation. 72.5 g of siloxane b was obtained. Obtained polyorganosiloxane b
Has an average particle size of 0.3 μm and a ratio of major axis to minor axis of 1.
The particles were spherical particles having a diameter of 01 or less.

Synthesis of polyorganosiloxane c As with polyorganosiloxane a, water 658 m
l, 28% ammonia water 8.3 g, ethyl orthosilicate 93.8 g (0.45 mol), methyltrimethoxysilane 54.5 g (0.40 mol) and vinyltrimethoxysilane 22.2 g (0.15 mol) Hydrolysis and polycondensation were carried out using the mixture described above to obtain 101.0 g of polyorganosiloxane c. The obtained polyorganosiloxane c was fine spherical particles having an average particle size of 1.2 μm and a ratio of major axis to minor axis of 1.02.

Synthesis of polyorganosiloxane d As with polyorganosiloxane a, water 658 m
l, 28% ammonia water 8.3 g, di (methacryloyloxypropyl) dimethoxysilane 22.9 g (0.0
67 mol) and 126.9 g of methyltrimethoxysilane
Hydrolysis and polycondensation were carried out using a mixture of (0.933 mol) to give 82.5 g of polyorganosiloxane d.
Obtained. The obtained polyorganosiloxane d was fine spherical particles having an average particle diameter of 2.6 μm and a ratio of major axis to minor axis of 1.01.

Synthesis of polyorganosiloxane e As in the case of polyorganosiloxane a, water 658 m
l, 28% ammonia water 8.3 g, vinylmethyldimethoxysilane 33.0 g (0.25 mol), octamethylcyclotetrasiloxane 50.3 g (0.17 mol) and methyltrimethoxysilane 9.5 g (0.07) Mol)
Hydrolysis and polycondensation were carried out using the mixture described above to obtain 76.1 g of polyorganosiloxane e. The obtained polyorganosiloxane e was an amorphous particle.

Synthesis of polyorganosiloxane r-1 As with polyorganosiloxane a, water 658 m
Hydrolysis and polycondensation were carried out using a mixture of 8.3 g of 28% aqueous ammonia and 136.0 g (1.0 mol) of methyltrimethoxysilane to obtain 68.0 g of polyorganosiloxane r-1. The obtained polyorganosiloxane r-1 was a fine spherical particle having an average particle diameter of 1.2 μm and a ratio of major axis to minor axis of 1.02.

Synthesis of polyorganosiloxane r-2 As with polyorganosiloxane a, water 658 m
l, 28% ammonia water 8.3 g, dimethyldimethoxysilane 135.0 g (0.9 mol), methyltrimethoxysilane 6.8 g (0.05 mol) and ethyl orthosilicate 6.7 g (0.05 mol) With the mixture,
Hydrolysis and polycondensation were performed to obtain 68.0 g of polyorganosiloxane r-2. The obtained polyorganosiloxane r-2 was rubber-like amorphous particles.

[0033]

[Table 1]

In Table 1, A / B: A-1 to A-4: Siloxane units represented by the following formulas 7 to 10, B-1 to B-4: Represented by the following formulas 11 to 14, respectively. Siloxane unit C-1: Terminal silyl group represented by the following formula 15

[0035]

[Formula 7]

[Formula 8]

[Formula 9]

[Formula 10]

[Formula 11]

[Formula 12]

[Formula 13]

[Formula 14]

[Formula 15]

Test Category 2 (Preparation of Radical Curable Resin Composition and Production of Cured Product by Optical Stereolithography Using the Same and Evaluation thereof) Preparation of Radical Curable Resin Composition The materials used are shown below. Radical curable resin 100
Parts by weight, 5 parts by weight of the photopolymerization initiator, and polyorganosiloxane, other fine particles or thermoplastic polymer to be added at the ratios shown in Table 2 or Table 3 in a mixing container and homogenized using a paint shaker. A radical-curable resin composition was prepared by stirring and mixing until it became. In addition, when the thermoplastic polymer was added, the one which had been uniformly dissolved in 100 parts by weight of the radical curable resin in the ratio shown in Table 3 was used.

.. Materials used Radical curable resin: glycerin monoacrylate / monomethacrylate / 2-hydroxyethyl methacrylate / tolylene diisocyanate = 1/1/1 (molar ratio)
60 parts of unsaturated urethane obtained by reacting with 40% triethoxylated trimethylolpropane triacrylate 40
Unsaturated urethane resin dissolved in 1 part Photopolymerization initiator: 1-hydroxycyclohexyl phenyl ketone (trade name Irgacure 184, manufactured by Ciba-Geigy) Polyorganosiloxane: Other fine particles using those shown in Table 2 are shown in Table 3. Thermoplastic polymer used as shown: used as shown in Table 3

Production of cured product and its evaluation Mainly composed of a three-dimensional NC table equipped with a container filled with the radical curable resin composition prepared above and a helium / cadmium laser light (wavelength 3250 angstrom) control system. A surface of the radical-curable resin composition was irradiated with a helium / cadmium laser beam focused from the vertical direction using an optical three-dimensional modeling device to model a disk having a diameter of 150 mm and a thickness of 10 mm. Then, the shaped disk was cut into a length 127 mm × width 12.7 mm using a diamond cutter to prepare a test piece. With respect to this test piece, cure shrinkage, heat distortion temperature, bending strength and tensile strength were measured by the following methods. The results are shown in Tables 2 and 3.

Curing shrinkage: The density D _{1 of the} test piece and the density D ₂ of the radical curable resin used for molding were measured, and the curing shrinkage was calculated by the following formula: Curing shrinkage (%) = [ (1 / D ₂ )-(1 / D ₁ ) / (1
/ D ₂ )] × 100 ・ ・ Heat deformation temperature: Measured according to JIS-K6919 ・ ・ Bending strength: Measured according to JIS-K6919 ・ ・ Tensile strength: Measured according to JIS-K6919

[0040]

[Table 2]

[0041]

[Table 3]

In Tables 2 and 3, the amount used: parts by weight a to e, r-1, r-2: polyorganosiloxane synthesized in Test Category 1 * 1: Silica fine particles (average particle diameter 1.2 μm) * 2: Styrene-divinylbenzene copolymer cross-linked polymer * 3: Polyisobutyl methacrylate (average molecular weight about 5
0000) * 4: Polypropylene adipate (average molecular weight about 550
0)

Test Category 3 (Production of cured product by cast molding method and its evaluation) Preparation of radical curable resin composition Radical curable resin 100 shown below as a material to be used
Parts by weight, 1 part by weight of radical initiator and 0.0
Radical-curable resin compositions having the proportions shown in Table 4 were prepared in the same manner as in Test Category 2 except that 075 parts by weight was used.

.. Materials used Radical curable resin: 0.01 parts of hydroquinone and 50 parts of styrene were added and dissolved in 100 parts of an unsaturated polyester (acid value 31) obtained by reacting propylene glycol with maleic anhydride. Unsaturated polyester resin Radical initiator: Methyl ethyl ketone peroxide Curing accelerator: Cobalt naphthenate Polyorganosiloxane: Other fine particles using those shown in Table 4 Other fine particles: Thermoplastic polymer using those shown in Table 4 The one shown in 4 was used

Production of cured product and its evaluation The radical-curable resin composition prepared above was applied to a thickness of 5 mm.
Sandwiching a polyethylene tube with an outer diameter of 5 mm between two glass plates (25 cm x 25 cm) and pouring it into a casting tank having a clearance of 3 mm, and holding the casting tank in a constant temperature bath at 35 ° C for 2 hours to obtain a cured product. Got The cured product was taken out of the casting tank and post-cured at 80 ° C. for 12 hours. The cured product obtained here was subjected to the following test. The results are shown in Table 4.
It was shown to.

· Appearance of cured product: The degree of warpage and cracks was visually observed and judged according to the following criteria. ⊚: No cracks or warpages at all ○: Almost no cracks or warpages △: Slight cracks or warpages ×: Many cracks or warpages ・ Heat deformation temperature, bending strength and tensile strength: Test Category 2
According to the method shown in

[0047]

[Table 4]

In Table 4, the amount used: parts by weight a to e, r-1, r-2, * 1 to * 4: the same as in Tables 2 and 3 * 5: calcium carbonate (average particle diameter 2 μm, trade name S-
Lite1200, manufactured by Nitto Koka Kogyo Co., Ltd.)

[0049]

As is apparent from the above, the present invention described above has the effect of preventing the shrinkage of the radical-curable resin during curing and the reduction in strength of the resulting cured product.

Claims (5)

[Claims] 1. When curing a radical-curable resin, 1 to 300 parts by weight of the following polyorganosiloxane is added to 100 parts by weight of the radical-curable resin to cure and shrink the radical-curable resin. A method for preventing reduction in strength of the cured product. Polyorganosiloxane: A siloxane which is mainly composed of one or more kinds of siloxane units selected from the following group A and one or more kinds of siloxane units selected from the following group B, and which is a group A siloxane Unit / B group of siloxane units = 1/99 to 30/70 (mol%) in a ratio of polyorganosiloxane A group; siloxane unit represented by the following formula 1, siloxane unit represented by formula 2 and formula 3 Siloxane unit represented by Group B: Siloxane unit represented by the following Formula 4, siloxane unit represented by Formula 5, and siloxane unit represented by Formula 6 below: [Formula 2] [Formula 3] [Formula 4] [Formula 5] [Formula 6] In formulas 1 to 6, X ^{1 to} X ⁴ are organic groups having a carbon atom directly bonded to a silicon atom and having an α, β-ethylenically unsaturated group R ^{1 to} R ⁴ : directly bonded to a silicon atom Non-radical polymerizable, substituted or unsubstituted hydrocarbon group having 2. The polyorganosiloxane is one or two selected from a siloxane unit represented by formula 3, a siloxane unit represented by formula 5, and a siloxane unit represented by formula 6.
The method for preventing cure shrinkage of a radical-curable resin and the strength reduction of the cured product thereof according to claim 1, wherein the total amount of one or more siloxane units is 15 mol% or more in all siloxane units. 3. The method for preventing cure shrinkage of a radical-curable resin and strength reduction of the cured product thereof according to claim 2, wherein the polyorganosiloxane is a spherical particle having an average particle diameter of 0.1 to 30 μm. 4. The radical-curable resin contains one or more ethylenically unsaturated monomer components selected from unsaturated polyesters, unsaturated oligoesters, unsaturated urethanes and unsaturated oligourethanes. Claim 1,
A method for preventing the shrinkage of the radical-curable resin according to 2 or 3 and the strength reduction of the cured product thereof. 5. The method according to claim 1, wherein the curing method is a photo-curing method.
A method for preventing the shrinkage of the radical curable resin according to 2, 3 or 4 and the strength reduction of the cured product thereof.