JPH04246414A - Shrinking inhibitor for unsaturated polyester resin - Google Patents

Abstract

PURPOSE:To obtain the title inhibitor with excellent effect on suppressing curing shrinkage when an unsatd. polyester resin is molded by specifying the specific gravity of a high mol.wt. satd. copolyester in the high mol.wt. satd. copolymerized polyester obtd. from a specified acid ingredient and a specified glycol ingredient. CONSTITUTION:A high mol.wt. satd. copolyester obtd. from 60-100 mole % (hereafter described as %) arom. dicarboxylic acid (e.g. terephthalic acid and isophthalic acid) and 0-40% aliph. dicarboxylic acid (e.g. sebacic acid) as the acid ingredients and 20-100% compd. of the formula (wherein R1 and R2 are each a 1-8C alkyl) and 0-80% other glycol (e.g. ethylene glycol) as the glycol ingredients, wherein the specific gravity is 1.20 (at 30 deg.C) or smaller.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a low-shrinkage agent that suppresses curing shrinkage during molding of thermosetting resins. More specifically, the present invention relates to a high molecular weight copolyester-based low-shrinkage agent that suppresses curing shrinkage of unsaturated polyester resins.

[0002] Unsaturated polyester resin is used as a thermosetting resin for cast molding, FRP molding, prepreg molding, premix molding, cold press molding, sheet molding compound molding (SMC), and bulk molding.
Molding Used as a molding material for compound molding (BMC), composite molding, etc., building materials,
Widely used for ships, automobiles, etc.

0003

[Problems to be Solved by the Invention] The unsaturated polyester resin is an unsaturated polyester resin having a copolymerizable unsaturated group (
A) and a copolymerizable monomer (B), and is generally molded by curing at room temperature or by heating using an organic peroxide as a catalyst, but it shrinks by about 8 to 10% during curing. is normal. Shrinkage during the curing stage not only causes distortion at the interface with the glass fibers and inorganic fillers used as reinforcing materials, leading to a decrease in mechanical strength, but also reduces the dimensional stability of the molded product and the smoothness of the surface of the molded product. It has a negative effect on sexuality.

0004

[Prior Art] In order to improve the above-mentioned drawbacks of unsaturated polyester resins, it is widely practiced to blend thermoplastic resins, such as vinyl acetate polymers, styrene polymers, and saturated copolymer polyesters, for the purpose of suppressing shrinkage. ing. However, due to the increasing sophistication of the industry's product requirements, the current situation is that conventional low-shrinkage agents cannot meet the demands. There was a strong demand from the industry for the development of a new drug.

[0005]

[Means for Solving the Problems] In view of the above-mentioned problems, the present inventors have conducted research into a low-shrinkage agent with a large shrinkage-lowering effect, and as a result of extensive research, they have found that certain copolymerized polyesters have specific properties. The present invention was achieved by discovering that a low shrinkage effect is exhibited. That is, the present invention uses 60 to 100 mol% of aromatic dicarboxylic acids and 0 to 100 mol% of aliphatic dicarboxylic acids as acid components.
40 mol%, general formula (I) as glycol component

[chemical 2
] (R1 and R2 are alkyl groups having 1 to 8 carbon atoms) 40 to 100 mol% and other glycols 0
A low-shrinkage unsaturated polyester resin, which is a high molecular weight saturated copolyester synthesized from ~60 mol %, characterized in that the high molecular weight saturated copolyester has a specific gravity of 1.20 or less at 30°C. It is a drug.

The low shrinkage agent for unsaturated polyester resins of the present invention comprises a high molecular weight saturated copolymer polyester. The acid components used in the production of the high molecular weight saturated copolyester of the present invention include aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, orthophthalic acid, and naphthalene dicarboxylic acid, succinic acid, adipic acid, azelaic acid, sebacic acid, Examples include aliphatic dicarboxylic acids such as dodecanedioic acid, tetrahydrophthalic acid, and hexahydrophthalic acid.

As the glycol component, the compound represented by the general formula (I) and other glycols are used. General formula (
Compounds represented by I)

Representative examples of (R1 and R2 are alkyl groups having 1 to 8 carbon atoms) include neopentyl glycol, 2,2-dimethylolbutane, 3,3-dimethylolpentane, 3,3
- Examples include dimethylolheptane.

Glycol components that can be used in combination with the compound represented by formula (I) include ethylene glycol, propylene glycol, 1,4-butanediol, diethylene glycol, 1,6-hexanediol, 1,9-nonanediol, and bisphenol. Examples include ethylene oxide or propylene oxide adducts of A, cyclohexanedimethanol, dimethyloltricyclodecane, and the like. If necessary, aromatic polyhydric carboxylic acids such as trimellitic acid and pyromellitic acid, and polyhydric alcohols such as glycerin, trimethylolpropane, and pentaerythritol can also be used in combination.

The high molecular weight saturated copolyester used in the present invention contains an aromatic dicarboxylic acid of 60 to 10 as an acid component.
It is essential to contain 0 mol % and 0 to 40 mol % of aliphatic dicarboxylic acid. If the content of the aliphatic dicarboxylic acid exceeds 40 mol %, it is not preferable because it lowers the mechanical strength of the unsaturated polyester resin after curing and adversely affects water resistance and alkali resistance.

[0010] Furthermore, it is essential that the glycol component contains 20 to 100 mol% of the compound represented by the general formula (I), more preferably 40 to 100 mol%. When the content of the compound represented by the general formula (I) is less than 20 mol %, the shrinkage-reducing effect is small and the solubility in the unsaturated polyester resin described later tends to be poor.

The high molecular weight saturated copolyester used in the present invention has a reduced viscosity (dl/g) of 0.4 or more, a number average molecular weight of about 10,000 or more, and more preferably a reduced viscosity (dl/g) of 0.4 or more. 6 or more, number average molecular weight is approximately 20.0
00 or more. The specific gravity at 30% of the high molecular weight saturated copolyester used in the present invention is 1.20 or less, more preferably 1.17 or less. When the specific gravity at 30° C. exceeds 1.20, the shrinkage reduction effect tends to decrease.

The unsaturated polyester resin used in the present invention is composed of an unsaturated polyester (A) and a copolymerizable monomer (B).
). Unsaturated polyester (A) is a polymer having α,β-ethylene saturated bonds in the molecule,
Such polymers include, for example, α,β-ethylenically unsaturated carboxylic acids such as maleic acid and fumaric acid or their anhydrides as acid components, and if necessary, saturated polycarboxylic acids such as adipic acid, phthalic acid, and tetrahydrophthalic acid. Unsaturated polyester obtained by reacting an acid with a polyol such as ethylene glycol, propylene glycol, or neopentyl glycol, an epoxy compound having two or more epoxy groups in the molecule, and α,β-ethylene such as acrylic acid or methacrylic acid. Epoxy acrylates, organic polyisocyanate compounds, polyester polyols, polyether polyols, etc. obtained by reaction with carboxylic acids containing system unsaturated groups, and α,β-ethylenic unsaturated compounds such as hydroxyethyl acrylate, hydroxyethyl methacrylate, etc. In addition to urethane acrylate containing a saturated group and obtained by reacting an isocyanate group with a compound having active hydrogen, polyether acrylate, oligoester acrylate, silicone acrylate, etc. may be mentioned.

Examples of the copolymerizable monomer (B) include styrene monomers such as styrene, vinyltoluene, divinylbenzene, t-butylstyrene, and 2,5-dichlorostyrene, diallyl phthalate, diethylene glycol bisallyl carbonate, and diallyl ether. , allyl monomers such as triallyl cyanurate and triallyl phosphate, (meth)acrylates such as methyl (meth)acrylate, ethyl (meth)acrylate, ethylene glycol di(meth)acrylate, and trimethylolpropane tri(meth)acrylate. Examples include monomers, vinyl ester monomers such as vinyl acetate, and the like.

The weight ratio of the unsaturated polyester (A) and the copolymerizable monomer is usually 80:20 to 30:70, preferably 60:40 to 40:60. The blending ratio of the low shrinkage agent for unsaturated polyester resin of the present invention is 1 to 20% of the unsaturated polyester resin.
% by weight, preferably 3-10% by weight.

The unsaturated polyester resin used in the present invention can be cured at room temperature or under heat using a conventionally known organic peroxide and, if necessary, an accelerator such as a metal salt or amine. Further, if necessary, UV curing or electron beam curing can be performed using a photosensitizer or the like. The unsaturated polyester resin used in the present invention may optionally contain reinforcing materials such as glass fibers and synthetic fibers, fillers such as calcium carbonate and aluminum hydroxide, thixotropic agents such as finely powdered silica, plasticizers, and colorants. , and other additives may be blended.

(Function) Since the low shrinkage agent for unsaturated polyester resin of the present invention contains the compound represented by the general formula (I) in the high molecular weight saturated copolyester skeleton, the free volume in the unsaturated polyester resin is It is believed that this is the reason why it exhibits a low shrinkage effect that cannot be achieved with conventional high molecular weight saturated copolyester polyesters.

(Examples) Examples will be given below to explain the present invention more specifically, but of course the present invention is not limited to the examples in any way. In the examples, parts simply indicate parts by weight. Each measurement item was performed according to the following method. Reduced viscosity ηsp/c (dl/g) 0.10g of high molecular weight saturated copolyester was mixed with phenol/
1,1,2,2,-tetrachloroethane (volume ratio 6/4
) was dissolved in 25 cc of a mixed solvent and measured at 30°C. Specific Gravity The specific gravity of the high molecular weight saturated copolyester was determined at 30° C. by the float-sink method using a density gradient tube. Glass transition temperature was measured using a differential scanning calorimeter (DSC) at a heating rate of 20° C./min. Composition analysis of high molecular weight saturated copolyester N. M. R
．． Compositional analysis was performed using

Synthesis example of polyester resin: In a stainless steel autoclave equipped with a stirrer, a thermometer and a partial reflux condenser, 2 moles of diterephthalate, 1 mole of phthalic anhydride, 1 mole of sebacic acid and 2,2 neopentyl glycol are added. 0.03 mol % of tetrabutyl titanate based on the total acid components as a polymerization catalyst was charged, and the esterification reaction was carried out at 180°C to 230°C for 5 hours, and then the reaction system was depressurized to 5 mmHg over 30 minutes. During this time, the temperature was raised to 250°C. Furthermore 0.3mmHg
Polycondensation was carried out at 250° C. for 30 minutes. Table 1 shows the properties of the obtained high molecular weight saturated copolymerized polyester (A). Similarly, high molecular weight saturated copolyesters (B) to (F) were synthesized using various acid components and glycol components. Its properties are shown in Table 1.

[0019]

[Table 1]

Examples 1 to 4 and Comparative Examples 1 to 2 High molecular weight saturated copolymer polyesters (A) to (F
) were each dissolved in styrene to a concentration of 30% by weight to obtain a styrene solution. 25 parts of each of the obtained styrene solutions of the high molecular weight saturated copolymerized polyesters and 75 parts of unsaturated polyester resin (isophthalic acid-based unsaturated polyester resin manufactured by Nippon U-Pica, containing 40% by weight of styrene) were mixed to form an unsaturated polyester resin composition. was prepared, mixed with 1 phr of benzoyl peroxide, cast, and cured at 80°C for 2 hours and then at 120°C for 2 hours, and the shrinkage rate of the cured product was measured. The shrinkage rate of the cured product was determined by measuring the difference in specific gravity before and after curing. The results are shown in Table 2.

[0021]

[Table 2]

(Effects of the Invention) The low shrinkage agent for unsaturated polyester resins of the present invention is a high molecular weight saturated copolymer polyester mainly consisting of an aromatic dicarboxylic acid and the glycol component of the general formula (I). It has an extremely low shrinkage effect compared to polyester-based low-shrinkage agents, and it solves all the problems caused by the shrinkage of unsaturated polyester resins at once.It has great industrial significance, and is useful not only for unsaturated polyester resins but also for other types of resins. It is also extremely useful as a low shrinkage agent for molding materials.

[C4]

Claims (1)

[Claims] 60 to 100 mol% of aromatic dicarboxylic acid as the acid component,
0 to 40 mol% of aliphatic dicarboxylic acid, 20 to 100 mol% of a compound represented by the following general formula (I) as a glycol component (R1 and R2 are alkyl groups having 1 to 8 carbon atoms), and other glycols. 0
Low shrinkage for unsaturated polyester resin, which is a high molecular weight saturated copolymerized polyester synthesized from ~80 mol%, the specific gravity of the high molecular weight saturated copolyester at 30°C is 1.20 or less agent.