JP2014019836A - Resin composition for putty, and putty obtained by curing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resin composition for a putty, having appropriate hardness and satisfying aspects of dimensional accuracy, adhesion and abradability.SOLUTION: A resin composition for a putty contains (A) an unsaturated polyester resin, (B) an ethylenically unsaturated monomer, (C) a low constrictive agent and (D) a filler, and (C) the low constrictive agent is an A-B type block copolymer containing an A segment which is a polymer based on a monomer containing vinyl acetate and a B segment which is a polymer based on styrene, and a percentage of the A segment in the A-B type block copolymer is 30 to 50 mass% and a percentage of B segment is 70 to 50 mass%, and a number average molecular weight of the A-B type block copolymer is 10,000 to 100,000.

Description

  In addition to repairing vehicles such as automobiles and trains, the present invention is a putty resin composition that can be used for sealing joints in buildings, around sashes, and inset parts of glass, and by curing this resin composition. Regarding the putty obtained.

Various putties are used for repairing automobiles and other vehicles and sealing joints in buildings. For example, when repairing damaged parts such as the outer panels of vehicles such as automobiles, After the film is peeled off, the putty is applied and dried, then polished and surfaced, and the surface of the surfaced putty is painted.
As putty used for vehicle repair, unsaturated polyester resins are widely used in terms of curability, drying properties, polishing properties, adhesion, and the like. However, since the putty is radically curable, curing shrinkage occurs at the time of curing, and it is likely that problems of dimensional accuracy such as warpage of the base material, putty trace, recess of the putty joint, and poor putty adhesion are likely to occur. There is.

In order to improve these drawbacks, in the putty resin material described in Patent Document 1, a polystyrene-based low shrinkage agent is blended as a low shrinkage agent for unsaturated polyester resin.
However, polystyrene and other thermoplastic resin-based low shrinkage agents are all formulated based on the idea of offsetting the curing shrinkage of the unsaturated polyester resin by the thermal expansion of the thermoplastic resin. At present, it is hardly effective for the molding method. Also in the above method, some warping of the substrate is improved, but when the putty is thickly applied or when curing at high temperature using an infrared heater or the like to promote curing, There is a problem that warp occurs, and it is necessary to solve it.
Further, when a thermoplastic resin such as polystyrene having a low polarity is blended with an unsaturated polyester resin having a relatively high polarity and adhesiveness, the adhesiveness to the base material is weakened and peeling or the like is likely to occur. Therefore, there is a need for a solution that simultaneously satisfies dimensional accuracy and adhesion.

In addition, as described above, when repairing a damaged part such as an outer plate of a vehicle such as an automobile, it is necessary to apply a putty to the damaged part, dry it, and then polish it using a grinder or the like. There is a problem that fine powder generated by polishing powders in the work space or clogs the grindstone, thereby reducing workability, and the solution is required.
That is, conventionally, a putty resin composition that has an appropriate hardness and is satisfactory in terms of dimensional accuracy, adhesion, and polishing properties, and a putty obtained by curing the resin composition have not been obtained.

JP 2007-77176 A

  In view of the above-described problems, the present invention provides a putty resin composition that has an appropriate hardness and is satisfactory in terms of dimensional accuracy, adhesion, and polishing properties, and a putty obtained by curing the resin composition. Objective.

  As a result of intensive studies by the present inventors in order to achieve the above-mentioned object, by adding an AB type block copolymer having a specific segment to the putty resin composition, the shrinkage at the time of molding is extremely high. Small, good dimensional accuracy moldings can be obtained, good abrasiveness with little dusting during polishing, and putty with sufficient hardness and adhesion to substrates such as rust-proof steel sheets. I found out that

  That is, the present invention is a putty resin composition comprising (A) an unsaturated polyester resin, (B) an ethylenically unsaturated monomer, (C) a low shrinkage agent, and (D) a filler. Of the total 100 parts by mass of (A) unsaturated polyester resin and (B) ethylenically unsaturated monomer, (A) the amount of unsaturated polyester resin is 20 to 80 parts by mass, ( B) The amount of the ethylenically unsaturated monomer is 80 to 20 parts by mass, and (C) the A segment, which is a polymer based on a monomer containing vinyl acetate, and a weight based on styrene. It is an AB type block copolymer composed of a B segment which is a coalescence. The proportion of the A segment in the AB type block copolymer is 30 to 50% by mass, and the proportion of the B segment is 70 to 50% by mass. Yes, and a few blocks of AB type block copolymer The molecular weight is 10,000 to 100,000, and (C) the amount of the low shrinkage agent is 100 parts by weight in total of the blending amount of (A) unsaturated polyester resin and (B) ethylenically unsaturated monomer. The present invention relates to a putty resin composition characterized in that the amount is 3 to 15 parts by mass and the amount of (D) filler is 50 to 250 parts by mass.

  The A segment which is a polymer based on a monomer containing vinyl acetate may be a vinyl acetate homopolymer or a copolymer of vinyl acetate and fumaric acid diester.

  The present invention also relates to a putty obtained by curing the putty resin composition of the present invention.

  According to the putty resin composition of the present invention, the shrinkage at the time of molding is extremely small, a molded article with good dimensional accuracy can be given, the powder has a good abrasiveness with little dusting at the time of polishing, and rust prevention A putty having adhesion to a substrate such as a steel plate and sufficient hardness is obtained. That is, by curing the putty resin composition of the present invention, a putty having greatly improved dimensional accuracy, adhesion, and polishing properties can be obtained.

  Embodiments of the present invention will be described below. The putty resin composition of the present invention contains the following component (A), component (B), component (C), and component (D). Hereinafter, each component will be described.

[Component (A)]
The component (A) in the present invention is an unsaturated polyester resin, and includes a low-reactivity unsaturated polyester resin to a highly-reactive unsaturated polyester resin. Unsaturated polyester resins are usually produced using polybasic acids or their anhydrides and polyhydric alcohols, for example, α, β-unsaturated dibasic acids or their anhydrides, and saturated dibasic acids or their It can be produced by a condensation reaction between an anhydride 3 mixture and a polyhydric alcohol.

Examples of the α, β-unsaturated dibasic acid or anhydride thereof include maleic acid, fumaric acid, mesaconic acid, tetraconic acid, itaconic acid or anhydrides thereof, or alkyl esters thereof. Among them, one kind or a combination of two or more kinds is used.
Examples of the saturated dibasic acid or its anhydride include phthalic anhydride, orthophthalic acid, isophthalic acid, terephthalic acid, tetrahydrophthalic acid, halogenated phthalic anhydride, het acid, adipic acid, succinic acid, sebacic acid, or these These are used in combination of one or more of them.
Examples of polyhydric alcohols include ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, neopentyl glycol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, Propylene oxide or the like was added to diols such as 1,5-pentanediol, 1,6-hexanediol, cyclohexanedimethanol, 2,2,4-trimethyl-1,3-pentanediol, hydrogenated bisphenol, and bisphenol A. In addition to glycols, for example, triols such as trimethylolpropane can be used, and one or a combination of two or more of these can be used.

  In the unsaturated polyester resin in the present invention, in addition to the unsaturated polyester resin obtained from polybasic acid or its anhydride and polyhydric alcohols, this unsaturated polyester resin is an epoxy such as glycidyl methacrylate or bisphenol A type epoxy. Those modified with an isocyanate compound such as a compound, toluene diisocyanate, isopropenyl-dimethyl-benzyl isocyanate and the like are included.

[(B) component]
The component (B) in the present invention is an ethylenically unsaturated monomer and can be copolymerized with the unsaturated polyester resin of the component (A). Examples of the component (B) include alkenyl aromatic monomers such as styrene, α-methylstyrene, t-butylstyrene, vinyltoluene, alkyl esters of acrylic acid or methacrylic acid, vinyl acetate, and the like. Of these, styrene is particularly preferred.

The blending ratio of the (A) component unsaturated polyester resin and the (B) component ethylenically unsaturated monomer is the blend of (A) the unsaturated polyester resin and (B) the ethylenically unsaturated monomer. Of the total amount of 100 parts by mass, the blending amount of (A) the unsaturated polyester resin is 20 to 80 parts by mass, preferably 30 to 70 parts by mass. Moreover, the compounding quantity of (B) ethylenically unsaturated monomer is 80-20 mass parts, Preferably it is 70-30 mass parts.
When the component (A) exceeds 80 parts by mass or the component (B) is less than 20 parts by mass, there is a tendency that the component (B) necessary for curing is insufficient, resulting in poor curing. Moreover, when (A) component is less than 20 mass parts or (B) component exceeds 80 mass parts, there exists a tendency for the hardness of the putty obtained by hardening | curing the resin composition for putty to fall.

[Component (C)]
The component (C) in the present invention is a low-shrinkage agent, and is an AB block comprising an A segment that is a polymer based on a monomer containing vinyl acetate and a B segment that is a polymer based on styrene. It is a copolymer.

Examples of the polymer based on a monomer containing vinyl acetate include a vinyl acetate homopolymer based only on vinyl acetate and a copolymer based on a monomer mixture composed of vinyl acetate and fumaric acid diester.
Examples of the fumaric acid diester include dimethyl fumarate, diethyl fumarate, diisopropyl fumarate, dibutyl fumarate, dicyclohexyl fumarate, di (2-ethylhexyl) fumarate, and the like, one or more of these. Used in combination.
The ratio of the fumaric acid diester in the monomer mixture of vinyl acetate and fumaric acid diester is preferably 20% by mass or less (however, greater than 0% by mass). When the content exceeds 20% by mass, the compatibility between the AB block copolymer and the unsaturated polyester resin tends to be poor, and the putty obtained by blending the AB block copolymer. There is a tendency that the dimensional accuracy of a molded product molded from the resin composition for use is insufficient.

  A polymer based on styrene is a styrene homopolymer based solely on styrene.

In the specific AB block copolymer composed of the A segment and the B segment, the proportion of the A segment is 30 to 50% by mass, and preferably 40 to 50% by mass. And the ratio of B segment is 70-50 mass%, Preferably it is 60-50 mass%. When the proportion of the A segment is less than 30% by mass or the proportion of the B segment is more than 70% by mass, a sufficient low shrinkage effect tends not to be obtained. In addition, when the proportion of the A segment exceeds 50 mass% or the proportion of the B segment is less than 50 mass%, the viscosity of the putty resin composition obtained by blending the AB block copolymer is It tends to be excessively high and workability tends to be remarkably deteriorated, and the hardness of the molded product is lowered, so that cracks and peeling tend to occur.
In addition, the ratio of the A segment to the B segment in the AB type block copolymer can be determined by, for example, nuclear magnetic resonance spectroscopy. Specifically, the ratio of the area (integrated value) of the signal serving as an index of the monomer containing vinyl acetate constituting the A segment to the area (integrated value) of the signal serving as the index of styrene constituting the B segment. Can be obtained by converting into a mass ratio.

  The number average molecular weight of the AB type block copolymer is measured by gel permeation chromatography, and the number average molecular weight in terms of styrene is 10,000 to 100,000, preferably 30,000 to 60,000. It is. If it is less than 10,000, the dimensional accuracy of the molded product molded from the putty resin composition obtained by blending the AB type block copolymer may be insufficient, and 100,000 may be used. When exceeding, the viscosity of the putty resin composition obtained by blending the AB type block copolymer tends to be high, and the workability tends to deteriorate.

The AB type block copolymer in the present invention is a known monomer or monomer mixture constituting the A or B segment, for example, using polymer peroxide (described in JP-A-53-149918). It can be produced by an arbitrary polymerization method such as a bulk polymerization method, a suspension polymerization method or an emulsion polymerization method in a production process (described in Japanese Patent Publication No. 60-3327), and specifically, either A or B segment After the first stage polymerization reaction for performing one polymerization reaction, the second stage polymerization reaction for performing the polymerization reaction of the remaining segments is performed.
The amount of polymer peroxide used when used as a polymerization initiator for synthesizing the AB type block copolymer is based on 100 parts by mass of the monomer or monomer mixture constituting the A or B segment. 0.1 to 10 parts by weight is preferable.
The polymerization temperature during the polymerization is preferably 40 to 80 ° C. for the first stage polymerization reaction and 60 to 100 ° C. for the second stage polymerization reaction, and the polymerization temperature in the first stage polymerization reaction is the second stage polymerization reaction. It is preferably lower than the polymerization temperature in. Furthermore, the charging method of the monomer mixture constituting the A segment or the B segment includes batch charging, divided charging, continuous charging, and the like, and it is preferable to select appropriately according to the combination of monomers. And although superposition | polymerization time changes with the kind of monomer to be used, and its usage-amount, it is preferable that both the 1st stage polymerization reaction and the 2nd stage polymerization reaction are the range for 1 to 10 hours.

In addition, although the arbitrary copolymer by the homopolymer of each monomer or a monomer mixture may be by-produced at the time of manufacture of an AB type block copolymer, when using it as a low shrinkage agent in this invention. For this, the AB block copolymer may be purified, or the reaction product may be used as it is without purification.
Further, in the preparation of the putty resin composition of the present invention, the AB type block copolymer which is a low shrinkage agent may be used as it is, or the concentration of the unsaturated polyester resin which is the component (A). It may be dissolved in advance in a solvent for adjustment (such as styrene) or an ethylenically unsaturated monomer as component (B).

[Component (D)]
The component (D) in the present invention is a filler, and only typical examples include calcium carbonate, magnesium carbonate, barium sulfate, mica, talc, kaolin, clay, celite, asbestos, barlite, baryta. And silica, silica sand, dolomite, limestone, gypsum, fine aluminum powder, hollow balloon, alumina, glass powder, aluminum hydroxide, cryolite, zirconium oxide, antimony trioxide, titanium oxide, and molybdenum dioxide. These fillers are selected in consideration of workability and the strength, appearance, economy, etc. of the molded product to be obtained. Usually, calcium carbonate, aluminum hydroxide, silica, talc and the like are used. In addition, you may use the surface-treated thing as a filler.

[Putty resin composition]
The resin composition for putty according to the present invention is based on 100 parts by mass of the total amount of (A) unsaturated polyester resin and (B) ethylenically unsaturated monomer. Is 3 to 15 parts by mass, preferably 7 to 12 parts by mass. (C) When the amount of the low shrinkage agent is less than 3 parts by mass, the dimensional accuracy of the molded product molded from the putty resin composition obtained by blending the AB block copolymer is insufficient. When the amount exceeds 15 parts by mass, the viscosity of the putty resin composition becomes too high, and the workability tends to be remarkably deteriorated.

  Moreover, the compounding quantity of (D) filler is 50-250 mass parts with respect to 100 mass parts of total quantities of the compounding quantity of (A) unsaturated polyester resin and (B) ethylenically unsaturated monomer. is there.

  In the putty resin composition of the present invention, a solvent may be blended as a diluent. Examples of particularly typical ones include toluene, xylene, methanol, ethanol, propanol, butanol, ethyl acetate, butyl acetate, acetone, methyl ethyl ketone, and the like.

  The putty resin composition of the present invention may contain a curing accelerator, a polymerization inhibitor, a colorant and the like for adjusting the curing rate.

  Examples of the curing accelerator include metal soaps such as cobalt naphthenate, cobalt octylate, zinc octylate, vanadium octylate, copper naphthenate, and barium naphthenate, vanadium acetyl acetate, cobalt acetyl acetate, iron acetylacetonate and the like. Metal chelates, aniline, N, N-dimethylaniline, N, N-diethylaniline, p-toluidine, N, N-dimethyl-p-toluidine, N, N-bis (2-hydroxyethyl) -p-toluidine, 4- (N, N-dimethylamino) benzaldehyde, 4- [N, N-bis (2-hydroxyethyl) amino] benzaldehyde, 4- (N-methyl-N-hydroxyethylamino) benzaldehyde, N, N-bis (2-hydroxypropyl) -p-toluidine, N-ethyl-m -N, N-substituted anilines such as toluidine, triethanolamine, m-toluidine, diethylenetriamine, pyridine, phenylmorpholine, piperidine, N, N-bis (hydroxyethyl) aniline, diethanolaniline, N, N-substituted-p -Amines such as toluidine and 4- (N, N-substituted amino) benzaldehyde.

  The compounding quantity of a hardening accelerator shall be 0.1-5 mass parts with respect to 100 mass parts of total amounts of the compounding quantity of (A) unsaturated polyester resin and (B) ethylenically unsaturated monomer. Is preferred. In addition, a hardening accelerator can be used by 1 type, or 2 or more types of combination, Furthermore, you may mix | blend with the putty resin composition previously and may mix | blend it at the time of use.

  Examples of the polymerization inhibitor include trihydrobenzene, toluhydroquinone, 1,4-naphthoquinone, parabenzoquinone, hydroquinone, benzoquinone, hydroquinone monomethyl ether, p-tert-butylcatechol, 2,6-di-tert-butyl-4. -A methylphenol etc. can be mentioned. The blending amount of the polymerization inhibitor is 0.001 to 0.1 parts by weight with respect to 100 parts by weight of the total blending amount of (A) unsaturated polyester resin and (B) ethylenically unsaturated monomer. Preferably there is.

  Specific examples of the colorant include inorganic pigments such as titanium white and carbon black, and organic pigments such as phthalocyanine blue and quinacridone red, and various colorants depending on the hue. Can be used.

  Various other additives may be blended in the putty resin composition of the present invention. For example, viscosity modifiers such as viscosity reducers, defoaming agents, silane coupling agents, air blocking agents such as paraffin, ultraviolet absorbers, plasticizers, aggregates, flame retardants, stabilizers, reinforcing materials, etc. Also good.

[Putty obtained by curing the resin composition for putty]
The putty resin composition of the present invention is obtained by curing the putty resin composition of the present invention. To use the putty resin composition of the present invention as putty in various applications, (A) to initiate the reaction between the unsaturated portion of the unsaturated polyester resin and (B) the ethylenically unsaturated monomer In addition, a curing agent is usually added to the putty resin composition. Examples of the curing agent include a thermosetting agent that generates radicals by heat, an ultraviolet curing agent that generates radicals by active energy rays, and an electron beam curing agent.

Examples of the thermosetting agent include organic peroxides, and known ones such as ketone peroxide, diacyl peroxide, dialkyl peroxide, hydroperoxide, peroxyester, peroxyketal, and the like are used.
As the ultraviolet curing agent, for example, known compounds such as acylphosphine oxide, benzoin ether, benzophenone, acetophenone, and thioxanthone compounds are used.
As an electron beam hardening | curing agent, well-known things, such as halogenated alkylbenzene and a disulfide type compound, are used, for example.
The said hardening | curing agent is suitably selected according to molding conditions.
The addition amount of the curing agent is preferably 0.1 to 6 parts by mass with respect to 100 parts by mass of the putty resin composition. In addition, you may use a hardening | curing agent combining 1 type (s) or 2 or more types.
In addition, the curing agent may be blended in advance with the putty resin composition as long as it does not cure, but it is usually blended at the time of use, and the thermosetting agent is preferably blended at the time of use.

The putty of the present invention contains at least the components (A) to (D) above, and the curing agent is blended with the putty resin composition of the present invention kneaded into a paste, and cured by any method. The cured molded product. When a curing agent is blended in the putty resin composition of the present invention and cured to obtain a putty, heating is performed according to the working time (for example, drying time), the thickness of the target substrate, and the like. A drying method such as curing by means or curing by natural drying can be appropriately selected, and the drying time and the curing state can be arbitrarily adjusted even after putting.
For example, when the outside air temperature is low, a drying method using forced drying (heat drying) can be used, and when the outside air temperature is high, a drying method using natural drying can be used.

  Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples. In the following, “parts” represents parts by mass, and “%” represents mass standards.

[Production of AB type block copolymer (low shrinkage agent)]
(Production Example 1)
A glass reactor equipped with a thermometer, a stirrer and a condenser was charged with 300 parts of water, 15 parts of a 1.0% aqueous polyvinyl alcohol solution and 15 parts of a 10% aqueous solution of tribasic calcium phosphate. Next, 0.51 part of polymeric peroxide represented by the following formula (1) (hereinafter referred to as P · PO) is dispersed in the aqueous solution at room temperature for 1 hour, and then vinyl acetate (hereinafter referred to as VAc). ) 30 parts were charged, and polymerization was carried out at 60 ° C. for 3 hours (first stage polymerization reaction) with stirring while replacing the inside of the reactor with nitrogen. Thereafter, the mixture was cooled to room temperature, 70 parts of styrene (hereinafter referred to as St) was added to the reactor, impregnated at room temperature for 1 hour, then stirred at 80 ° C. for 7 hours, and then at 90 ° C. for 30 minutes. Polymerization (second stage polymerization reaction) was performed.
After cooling to room temperature, the polymer obtained was washed with 100 parts of 5% hydrochloric acid, followed by water, filtered, dried under vacuum, and 94 parts of a white pearl (solid) AB block copolymer. Got. A part of the polymer thus obtained was first extracted with a Soxhlet extractor for 24 hours using cyclohexane as an eluent and then for 24 hours using methanol as an eluent. Further, nuclear magnetic resonance spectroscopic analysis of the extraction residue was performed, and the ratio of the A segment to the B segment in the AB block copolymer (indicated as A / B in Table 1) was determined. 70. Furthermore, when the number average molecular weight of the extraction residue was measured by gel permeation chromatography, it was 42,000 in terms of polystyrene.

(Production Examples 2 to 7 and Comparative Production Examples 1 and 2)
With the composition shown in Table 1, AB type block copolymers according to Production Examples 2 to 7 and Comparative Production Examples 1 and 2 were produced. The yield of each of the obtained AB block copolymers, the ratio of the A segment to the B segment, and the number average molecular weight are shown in Table 1 together with Production Example 1.
In Table 1, DIPF is diisopropyl fumarate and DMF is dimethyl phthalate. In Production Examples 3 to 7, a mixture of monomers constituting the A segment was polymerized by a first stage polymerization reaction. Further, in Production Example 4, the amount of P · PO charged was 0.20 parts, and in Production Example 6, the amount of P · PO charged was 1.05 parts.

[Preparation of putty resin composition and putty]
(Example 1-1)
(A) Unsaturated polyester resin (manufactured by DH Material Co., Ltd., Sandoma (registered trademark) CN-703, solid content: about 65%) is added so that the solid content becomes 50%. 100 parts prepared with styrene, a saturated monomer,
(C) 9 parts of the AB type block copolymer (low shrinkage agent) obtained in Production Example 1;
(D) 150 parts of talc (talc SW: manufactured by Nippon Talc Co., Ltd., particle size: average 12 μm) as a filler,
2 parts of a cobalt-based accelerator (accelerator RP-136, manufactured by DIC Corporation),
0.5 parts of an amine accelerator (reagent: dimethylaniline) was added and stirred for 15 minutes with a high speed dissolver to obtain a putty resin composition.
In 100 parts of the obtained resin composition for putty, 0.75 parts of a curing agent: cumene hydroperoxide (manufactured by NOF Corporation: Park Mill H-80) and 0.75 parts of a curing agent: diacyl peroxide (Nippon Oil Co., Ltd. product: Niper BW) was added and sufficiently stirred to obtain a resin composition for putty containing a curing agent.

Putting the resin composition for putty containing the above curing agent on a rust-proof steel plate (manufactured by Engineering Test Service: Silver Zinc) (size: 70 mm × 150 mm × 0.8 mm) with a thickness of 2 mm, 25 It was allowed to stand for 24 hours under the condition of ° C. to be cured to obtain a putty.
The following evaluation tests were performed using the putty test pieces obtained. The results are summarized in Table 2.

(Evaluation of low shrinkage of putty)
The warp height of the test piece obtained by the above method was quantified. The sled height is the height of one of the horizontal plate and the test piece when the putty of the test piece is placed on the horizontal plate and one of the long sides of the test piece is pressed against the horizontal plate.

(Evaluation of putty adhesion)
Using the test piece obtained by the above method, the sample was allowed to stand at 25 ° C. for 24 hours (after 1 day), and then a 180 ° bending test was performed. Moreover, after leaving it to stand for 5 hours in a 120 ° C. dryer (120 ° C. × 5 h), it was cooled and subjected to a 180 ° bending test. Evaluation was performed according to the following criteria.
○: Cohesive failure, ×: Interfacial peeling

(Evaluation of abrasiveness of putty)
The test piece obtained by the above method was polished with # 240 paper, checked for clogging, and evaluated according to the following criteria.
○: No clogging, △: Some clogging, ×: Clogging

(Evaluation of putty hardness)
The Barcol hardness of the test piece obtained by the above method was measured with a Barcol hardness meter (product name: GYZJ935) manufactured by BARBER COLMAN. The putty requires a hardness of 60 or more. When the hardness is 59 or less, it is poorly cured and may cause defects such as cracks and peeling. Therefore, evaluation was performed according to the following criteria.
○: 60 or more, ×: 59 or less

(Examples 1-2, 2-1 to 2-13, Comparative Examples 1 to 10)
In Examples 1-2, 2-1 to 2-13, and Comparative Examples 1 to 10, the type of the low shrinkage agent, the blending amount of the low shrinkage agent, the blending amount of the unsaturated polyester resin, and the ethylenically unsaturated monomer, respectively. Example 1 except that the ratio of the filler to the blending amount, the type of filler (talc MS: manufactured by Nippon Talc Co., Ltd., particle size: average 14 μm), and the blending amount of the filler were changed to the blending shown in Table 2. According to -1, a putty resin composition and putty were obtained.
The obtained putty test pieces were evaluated according to Example 1-1, and the evaluation results are summarized in Table 2.

In Table 2, unsaturated polyester resin is referred to as UP resin.
Moreover, the comparative low shrinkage agent used in Comparative Examples 7 to 10 is manufactured by the following product or method.

PSt: PSt (polystyrene HF77) manufactured by PS Japan was used as a comparative low shrinkage agent PSt.
PVAc: 240 parts of vinyl acetate was dissolved in 60 parts of methanol, the reaction vessel was purged with nitrogen, the temperature was raised to 60 ° C., 0.045 part of AIBN was added as an initiator, and polymerization was carried out for 3 hours. Thereafter, the polymerization was stopped, and the polymer obtained by precipitation in hexane was vacuum-dried to obtain a polymer having a yield of 79 g. The obtained polymer was used as a comparative low shrinkage agent PVAc.
PVAc / PSt: A comparative low shrinkage agent PVAc / PSt was prepared by mixing PVAc and PSt of the above-mentioned comparative low shrinkage agent in equal amounts.
PVAc-r-PSt: A reaction vessel was charged with 300 parts of water, 15 parts of a 1.0% aqueous polyvinyl alcohol solution and 15 parts of a 10% aqueous solution of tribasic calcium phosphate. Next, 0.50 part of Parroyl L (manufactured by NOF Corporation), 50 parts of vinyl acetate and 50 parts of styrene were added, and polymerization was carried out with stirring at 80 ° C. for 7 hours and subsequently at 90 ° C. for 30 minutes. After cooling to room temperature, the polymer obtained was washed with 100 parts of 5% hydrochloric acid, followed by water, filtered, and dried under vacuum to obtain 94 parts of polymer. The obtained polymer was used as a comparative low shrinkage agent PVAc-r-PSt.

(Example 2-14)
(A) Unsaturated polyester resin (manufactured by DH Material Co., Ltd., Sandoma (registered trademark) CN-203, solid content: about 65%) is added so that the solid content becomes 50%. 100 parts prepared with styrene, a saturated monomer,
(C) 9 parts of the AB type block copolymer (low shrinkage agent) obtained in Production Example 5;
(D) 150 parts of talc (talc SW: manufactured by Nippon Talc Co., Ltd., particle size: average 12 μm) as a filler,
Three parts of a cobalt-based accelerator (accelerator RP-136, manufactured by DIC Corporation) was added, and the mixture was stirred with a high-speed dissolver for 15 minutes to obtain a putty resin composition.
To 100 parts of the obtained putty resin composition, 1.5 parts of a curing agent: cumene hydroperoxide (manufactured by NOF Corporation: Park Mill H-80) is added and stirred sufficiently to contain a curing agent. A putty resin composition was obtained.
A putty was obtained in accordance with Example 1-1 using the putty resin composition containing the curing agent. The obtained putty test pieces were evaluated according to Example 1-1, and the evaluation results are summarized in Table 2.

(Comparative Example 11)
In Comparative Example 11, a putty resin composition and putty were obtained according to Example 2-14, except that the low shrinkage agent was not blended.
The obtained putty test pieces were evaluated according to Example 1-1, and the evaluation results are summarized in Table 2.

  From the evaluation results of the above Examples and Comparative Examples, the putty resin composition of the present invention was cured by using an AB block copolymer having a specific segment as a low shrinkage agent. It can be seen that the dimensional accuracy, adhesion and polishing properties of the putty obtained are greatly improved.

Claims (4)

(A) an unsaturated polyester resin;
(B) an ethylenically unsaturated monomer;
(C) a low shrinkage agent;
(D) a putty resin composition comprising a filler,
Of the total 100 parts by mass of (A) unsaturated polyester resin and (B) ethylenically unsaturated monomer, (A) 20-80 parts by mass of unsaturated polyester resin, (B) The blending amount of the ethylenically unsaturated monomer is 80 to 20 parts by mass,
(C) The low shrinkage agent is an A-B type block copolymer comprising an A segment that is a polymer based on a monomer containing vinyl acetate and a B segment that is a polymer based on styrene,
In the AB type block copolymer, the proportion of the A segment is 30 to 50% by mass, the proportion of the B segment is 70 to 50% by mass, and the number average molecular weight of the AB type block copolymer is 10,000. ~ 100,000,
(A) 3-15 mass parts of compounding quantity of (C) low shrinkage agent with respect to 100 mass parts in total of the compounding quantity of unsaturated polyester resin and (B) ethylenically unsaturated monomer, (D) The putty resin composition, wherein the filler is blended in an amount of 50 to 250 parts by mass.   The putty resin composition according to claim 1, wherein the A segment, which is a polymer based on a monomer containing vinyl acetate, is a vinyl acetate homopolymer.   The putty resin composition according to claim 1, wherein the A segment, which is a polymer based on a monomer containing vinyl acetate, is a copolymer of vinyl acetate and fumaric acid diester.   The putty obtained by hardening | curing the resin composition for putty in any one of Claims 1-3.