JPH03221534A - Low contracting agent - Google Patents

Abstract

PURPOSE:To provide a low contracting agent useful for improving the smoothness, coloring property and storage stability of thermosetting resins in a plastic field, etc., by employing poly octamer as a main component. CONSTITUTION:For example, (A) 30-80 pts.wt. of an unsaturated polyester resin (preferably having a molecular weight of 1000-3000, an acid value of 10-50 and a hydroxyl group value of 5-60), (B) 70-20 pts.wt. of an ethylenically unsaturated monomer (e.g. styrene) and (C) polyoctenamar (prepared by polymerizing cyclooctene, having one double bond per eight carbon atoms and preferably having a molecular weight of >=1000, a crystallinity of >=5%, a glass transition temperature of -80 to -30 deg.C and a melting point of 5 to 80 deg.C) in an amount of 5-200 pts.wt. per 100 pts.wt. of the total amount of the components A and B are compounded to provide a low contacting unsaturated polyester resin composition.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a low shrinkage agent used in thermosetting resins such as unsaturated polyester resins.

(Prior Art and Problems) Thermosetting resins generally shrink in volume when cured. In particular, unsaturated polyester has a high single-injection shrinkage rate during curing, so molded products obtained from this resin by compression molding, injection molding, etc. may suffer from distortions, cracks, sink marks, etc., and lack of smoothness. There are drawbacks such as embossment of the glass fiber used for removal and molding.

In order to improve these drawbacks, for example, Japanese Patent Application Laid-Open No. 48-34
As disclosed in No. 289, unsaturated polyester resins include polystyrene, polymethyl methacrylate,
By mixing and curing anti-shrinkage thermoplastic polymers such as polyvinyl acetate, it has become possible to produce molded products with virtually no curing shrinkage, and the above-mentioned drawbacks have been greatly improved. .

However, ordinary anti-shrinkage thermoplastic polymers such as polystyrene, polymethyl methacrylate, and polyvinyl acetate have low dispersion stability in unsaturated polyester resin compositions, and when the mixture is left for 1 to 5 hours, the polymer rose to the top of the composition, and a good cured product was often not obtained.

Therefore, the present inventors conducted intensive studies to improve the drawbacks of the conventional low-shrinkage agents as described above, and as a result, they arrived at the present invention.

(Means for Solving the Problems) That is, the present invention is a low shrinkage agent containing polyoctenamer as a main component.

The polyoctenamer used in the present invention must be made by polymerizing cyclooctene, have one double bond per eight carbon atoms, have a molecular weight of 10,000 or more, and have a high degree of crystallinity. It is preferably 5% or more. Such polyoctenamer has a glass transition temperature of -80 to -3
It is in the range of 0°C, and its melting point is in the range of 5 to 80°C.

Various methods can be used to synthesize cyclooctene, which is the base material constituting this polyoctenamer. For example, it can be obtained by trimerizing butadiene and then hydrogenating one of the two remaining double bonds. It will be done.

Various methods can be employed to obtain polyoctenamer by polymerizing this cyclooctene, but for example, polymerization by metathesis polymerization is convenient because the degree of crystallinity can be easily controlled.

Various commonly used stabilizers, ultraviolet absorbers, plasticizers, colorants, etc. can also be added to the polyoctenamer used in the present invention. These various additives can be easily added to polyoctenamer using a common extruder for plastics.

Below, the use of the low shrinkage agent of the present invention will be explained in detail for an unsaturated polyester thermosetting resin. The low shrinkage unsaturated polyester resin composition containing the low shrinkage agent of the present invention has the following composition.

(A) Unsaturated polyester resin 30 to 80 parts by weight (B
) Ethylenically unsaturated monomer 70 to 20 parts by weight
(^) Component 10 (B) Component - 100 parts by weight (C) Polyoctenamer - 5 to 200 parts by weight (D) Inorganic photo-tensifying agent
40-400 parts by weight (E) reinforcing agent
10 to 200 weight 1 part (F) Polymerization initiator
0. O1 to 5 parts by weight Among these compositions, the unsaturated polyester resin (^) component is selected from α, β-unsaturated dibasic acids and glycols, or if necessary, a saturated dibasic acid is used in combination. Manufactured by

As the α,β-unsaturated dibasic acid, maleic anhydride, maleic acid, fumaric acid, mesaconic acid, tetraconic acid, itaconic acid, chlorinated maleic acid, etc. are used. Examples of the saturated dibasic acid include orthophthalic acid, phthalic anhydride, isophthalic acid, terephthalic acid, tetrahydrophthalic acid, halogenated phthalic anhydride, and esters thereof can also be used.

In addition, the glycols used here include ethylene glycol, propylene glycol, dipropylene glycol, butylene glycol, neopentyl glycol, hexylene glycol, hydrogenated bisphenol A, 2
．． Examples include 2'-di(4-hydroxypropoxyphenyl)propane, 2'2'-di(4-hydroxyethoxyphenyl)propane, ethylene oxide, propylene oxide, and the like.

Among these, the α, β-unsaturated dibasic acid in the acid component is 50
More than 50% by mole is required, and if it is less than 50% by mole, the desired low shrinkage effect cannot be obtained sufficiently. Particularly in the case of sheet mold compounding, it is better to have 100% α,β-unsaturated dibasic acid.

Melting method is used to produce unsaturated polyester using these materials.
Known manufacturing methods such as solution method and epoxy method are widely used.

The unsaturated polyester preferably has a molecular weight of 1000 to 3000, an acid value of 10 to 50, and a hydroxyl value of 5 to 60.

The ethylenically unsaturated monomer (B) a of the present invention is:
It is an unsaturated monomer having at least one ethylenic bond in one molecule. This unsaturated monomer must be capable of crosslinking and thermosetting by reacting with the unsaturated polyester (A), and must also dissolve the unsaturated polyester (^),
Furthermore, those that can also dissolve the saturated polyester (B) are preferred. Specific examples of the unsaturated monomer (B) include styrene, vinyltoluene, lower alkyl esters of acrylic acid or methacrylic acid (for example, methyl methacrylate, methyl acrylate, ethyl methacrylate, ethyl acrylate, propyl methacrylate). , propyl acrylate,
butyl methacrylate, butyl acrylate, 2-ethylhexyl methacrylate, 2-ethylhexyl acrylate)
, methacrylic acid, acrylic acid, divinylbenzene, chlorostyrene, α-methylstyrene, diaryl phthalate, ethylene glycol dimethacrylate, trimethylolpropane trimethacrylate, 2,5-dichlorostyrene, 25-dipromostyrene, pentabromophenol allyl ether , tribromophenyl acrylate, dialkylphosphonic acid, antimony trioxide, diallylbenzene phosphonate, tricresyl phosphate, triallyl phosphate, diallyl ethyl phosphate, methyl β-(methylethyl)phosphonoacrylate, (diallylphosphonomethyl) Examples include ether, but styrene is mainly used. Of course, each of these monomers can be used alone or in a mixture of two or more.

Examples of the inorganic filler as component (D) include silica, alumina, metal oxides such as iron oxide, zinc oxide, and magnesium oxide, metal hydroxides such as aluminum hydroxide, magnesium hydroxide, and iron hydroxide, and iron powder. , metal powder such as aluminum powder, asbestos powder, glass powder, calcium carbonate, magnesium carbonate, sodium sulfate, diatom, etc.

However, chopped strands and glass fiber mats with a fiber length of 3 to 25 m+* are excluded.

The particle size of the inorganic filler used is 0.1 to 100 microns, but preferably 30 microns or less. Moreover, among these, when a metal hydroxide is used in particular, it has the advantage that the viscosity of the resin composition is low.

Examples of reinforcing materials for component (E) include glass fiber, carbon fiber, asbestos, potassium titanate, whiskers, and metal fiber. The fiber length used is 3 to 25 m1.

In addition, as a polymerization initiator for component (F), organic polymers such as benzoyl peroxide, lauryl peroxide, methyl ethyl ketone peroxide, dicumyl peroxide, 2,5-di(peroxybenzoate) hexyne 3, and t-butyl perbenzoate are used. Oxides, azo compounds such as azobisisobutyronitrile, dimethylazodiisobutyronitrile, etc. can be used.

(A) component, (B) component, (C) component in the present invention,
There is no particular restriction on the blending ratio of component (D), component (E), and component (F), but from the viewpoint of mechanical strength and heat resistance, (
Component A) is 30 to 80 parts by weight, component (B) is 70 to 20 parts by weight.
5 to 2 parts of component (C) per 100 parts by weight in total
It is preferable to add 00 parts by weight.

If the amount of component (C) used is less than 5 parts by weight, the shrinkage improvement effect will not be sufficient, and if it is more than 200 parts by weight,
The heat distortion temperature becomes low, making it impractical.

In the resin composition to which the low shrinkage agent of the present invention is added, in addition to the (^) component, (B) component, (C) component, (D) component, (E) component, and (F) component, if necessary, Polymerization inhibitors, lubricants, pigments, dyes, and other materials used in the underground form material can be added accordingly.

It goes without saying that the use of the low shrinkage agent of the present invention is not limited to the above-mentioned unsaturated polyester resins, but can also be used for epoxy-based, urethane-based, and other thermosetting resins.

(Effect of the first day) The thermosetting resin composition to which the low-shrinkage agent of the present invention has been added has the following properties:
It has excellent storage stability, has a shrinkage rate of 0.5% or less, has uniform coloring, and can provide smooth cured products.

(Examples) Next, the present invention will be explained with reference to Examples, but the present invention is not limited by these.

Example 1 55 parts by weight of an unsaturated polyester resin obtained from maleic anhydride and 1,2-propylene glycol, 45 parts by weight of styrene, VESTENAMER 80 manufactured by Huls
50 parts by weight of 12, 1 part by weight of t-butylbabenzoate, 120 parts by weight of calcium carbonate, and 80 parts by weight of glass fiber with a fiber length of 1 clTl were kneaded in a kneader, and then kneaded at 40°C.
Leave to ripen for one day and apply bulk molding compound (
BMC) was obtained. This was pressed at 150° C. and a pressure of 100 kg/cj for 3 minutes to obtain a smooth plate with no uneven surface. The linear shrinkage rate was 0.04%, which was a good result.

Example 2 60 parts of the unsaturated polyester used in Example 1, 40 parts by weight of styrene, VESTENAME manufactured by Huls
30 parts by weight of R6213, 1 part by weight of t-butyl perbenzoate, 1 part by weight of Mg0, 3 parts by weight of zinc stearate, and 100 parts by weight of aluminum hydroxide were kneaded in a kneader, coated on a glass fiber mat, and then mixed with glass fibers. Quantity 10
The amount was adjusted to 0 parts by weight. Next, the glass fibers were sufficiently impregnated with the kneaded material by roll pressing, and heated at 40°C.
Leave it for a day and apply sheet molding compound (S
MC) was obtained.

This was pressed for 4 minutes at 140° and 100 kg/cj to obtain a plate with good surface smoothness and no warpage. This product had a good linear shrinkage rate of 0.06%.

Comparative Example In Example 1, a BMC was obtained in exactly the same manner as in Example 1, except that VESTENAMER 8012 was not added, and a plate was prepared from it by the pressing method in exactly the same manner as in Example 1. Glass fibers were slightly protruding from the surface of this product, the smoothness was poor, and it was distorted due to heat shrinkage.

of this plate Linear shrinkage rate is 0.7 %Met.

Claims (1)

[Claims] A low shrinkage agent whose main ingredient is polyoctenamer.