JPS61293256A - Shrinkage controlling agent - Google Patents

Abstract

PURPOSE:To provide a shrinkage controlling agent which gives a cured resin having excellent surface smoothness, consisting of a lactone polymer obtd. by reacting a polyester resin, a lactone and a tri- or polyhydric alcohol. CONSTITUTION:n mol of a polyhydric alcohol (e.g. ethylene glycol) is reacted with (n+1) mol of a polybasic acid (e.g. maleic acid) to obtain a polyester resin contg. a carboxyl group at its terminal and having an MW of 300-20,000. 30-95wt% lactone (e.g. epsilon-caprolactone), 0.8-8wt% tri- or polyhydric alcohol (e.g. diglycerol) and 0.01-50ppm of a catalyst (e.g. tetrabutyl titanate) are added to said polyester resin. The mixture is reacted in an inert atmosphere at 130-240 deg.C to obtain a shrinkage controlling agent composed of a lactone polymer having an MW of 500-100,000.

Description

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

(Prior art) Unsaturated polyester resin compositions have a high dimensional shrinkage rate (for example, 10%) upon curing, and therefore molded products obtained from the resin by mold molding, injection molding, etc. are prone to distortion, cracks, and distortion. There are disadvantages such as the occurrence of dust, lack of smoothness on the surface of the molded product, and embossment of the reinforcing fibers used for molding. In order to eliminate these drawbacks, various studies have been conducted in recent years, such as the invention disclosed in JP-A-8-34289, in which polystyrene, polymethyl methacrylate, etc. are added to unsaturated polyester resin. By mixing and curing anti-shrinkage thermoplastic polymers, it is possible to produce moldings with virtually no curing shrinkage, and the above-mentioned disadvantages have been considerably improved.

(Problems to be Solved by the Invention) However, ordinary anti-shrinkage thermoplastic polymers such as polystyrene, polymethyl methacrylate, etc. have low dispersion stability in unsaturated polyester resin compositions, and the mixture cannot be used for a while ( If the composition is left for 1 to 5 hours, the polymer tends to float to the top of the composition, and it also has poor compatibility with fillers and other inorganic fillers, resulting in poor dispersibility.

Low-shrinkage agents made of lactone polymers having various terminal groups have been proposed to improve these drawbacks, and one example of such agents is a reaction product of phthalic anhydride and a lactone polymer. There is. Although this has carboxyl groups at both ends, it has the disadvantage of poor solubility in the styrene monomer used at the same time when used as a low shrinkage agent. Beyond that, the reaction during synthesis does not proceed easily. Therefore, a lactone polymer obtained by ring-opening polymerization using ml of water and a compound having at least one carboxyl group as an initiator, and having at least one carboxyl group and one or more water F group as terminal groups. A patent application filed in 1982 shows that the combination has excellent solubility properties in styrene without impairing low shrinkage properties.
103206. However, compared to this lactone polymer having one or more carboxyl groups and one or more hydroxyl groups, a polymer having carboxyl groups at both ends obtained by a transesterification reaction between a polyester having carboxyl groups at the ends and lactones has an even better low shrinkage. The inventors of the present invention discovered that it has properties of styrene and solubility in styrene, and disclosed it in Japanese Patent Application No. 59-174179.

Further progress in this research revealed that when a polymer obtained by reacting a polyester with a carboxyl group at the end with a trihydric or higher alcohol and a lactone was used as a low-shrinkage agent, curing with particularly excellent surface smoothness was achieved. It was discovered that a resin can be obtained, leading to the present invention.

(Structure of the Invention) In other words, the present invention provides a polyester resin having a terminal carboxyl group synthesized from a polyhydric alcohol, a polybasic acid, or an anhydride thereof, and a polyester resin synthesized from a lactone and a trihydric or higher polyhydric alcohol. A low-shrinkage agent characterized by comprising a lactone polymer.

The lactones used in the present invention have 4 or more, preferably 6 or more carbon atoms in the ring. Preferred lactones are 5- to 8-membered ring lactones, such as ε-caprolactone, -8-a-lactone, and ρ-butyrolactone.

In addition, the polyhydric alcohols used in the present invention include dihydric and trihydric alcohols.
In addition, alcohols with a valence of 4 or higher are included, such as ethylene glycol, propylene glycol, 1,3-butylene glycol, 2-methylalpanediol, 1,4-
Butylene glycol, neopentyl glycol, 1,6
-hexanediol, 1,2-dodecanediol, glycerin, trimethylolpropane, trimethylolethane, pentaerythritol, dipentaerythritol,
Hydroxypivalic acid neopentyl glycol ester, 1,4-cyclohexane dimetatool, ethylene oxide adduct of bisphenol A, propylene oxide adduct of bisphenol A, and its water additive 4-human 1
Koxyhydroquinone and the like can be used. Or
These can be used together. Examples of the polybasic acid or anhydride thereof which is the second component of the polyester resin having a terminal carboxyl group used in the present invention include maleic acid, succinic acid, fumaric acid, adipic acid, sebacic acid, azelaic acid, dodecanedioic acid, Phthalic acid, isophthalic acid, terephthalic acid, hexahydrophthalic acid, methylhexahydrophthalic acid, tetrahydrophthalic acid, methyltetrahydrophthalic acid, trimellitic acid, or their anhydrides can be used. Alternatively, these can also be used in combination.

In the present invention, lactones are added to the lactone polymer from 30 to
It is necessary to contain 95% by weight.

If the content of lactones is less than 30% by weight, the water resistance and low temperature properties of the produced resin will deteriorate. On the other hand, if the amount is more than 95% by weight, the crystallinity of the lactones may result in poor compatibility with solvents or increase in the melting point of the lactone polymer, which is undesirable.

Now, a method for synthesizing the lactone polymer of the present invention will be described. First, polyhydric alcohol and polybasic acid are charged into a reactor.

At this time, when the number of moles of the polyhydric alcohol is n, the number of moles of the polybasic is added at a ratio of n+1. Reaction temperature is 100℃
React at ~230°C.

When a predetermined amount of water is dehydrated, a polynisdel with terminal carboxyl groups is obtained.

Although this reaction proceeds without a catalyst, a catalyst commonly used in esterification reactions may be used. Examples include sulfuric acid, valatoluenesulfonic acid, and titanium compounds such as tetrabutyl titanate. The molecular weight of the polyester with a terminal carbo-4-syl group obtained in this way was 300.
~20,000, preferably i,ooo~7,000. Also, those having a molecular weight distribution MW/HN of 2 to 15 are particularly effective as low-shrinkage agents.

Next, a lactone catalyst and a trihydric or higher polyhydric alcohol are added to the polyester resin so that the resin contains 30 to 95% by weight, preferably 60 to 90% by weight of the radokun, and the mixture is reacted. The reaction temperature is 130°C to 240°C, preferably 160°C to 230°C. Also, passing an inert gas such as nitrogen gas during the reaction gives good results on the hue of the resin.

Catalysts used in this reaction include titanium compounds such as tetrabutyl titanate and tetrapropyl titanate, dibutyltin laurate, tin octylate, dibutyltin oxide, stannous chloride, stannous bromide, and stannous iodide. .01-50 ppm.

It is preferable to use 0.1 to io ppm.

Furthermore, among these catalysts, titanium-based compounds in particular exhibit sufficient catalytic activity for transesterification reactions.

The trihydric or higher polyhydric alcohols used in the present invention include pentaerythritol, dipentaerythritol, diglycerin, polyglycerin, poval, celluloses, and saccharides.

One or more types of these polyhydric alcohols having a rating of 5 or more may be used. Since these polyhydric alcohols play the role of initiating polymerization of lactones, the amount added is preferably the minimum amount necessary to initiate polymerization of lactones.

If the amount of trihydric or higher polyhydric alcohol added is large, the water 11 value and acid value of the product will become high, which is not preferable.

Therefore, the amount added is preferably in the range of 0.1% to 8%.

Moreover, as a method for synthesizing the low shrinkage agent of the present invention, it is synthesized in advance with a polynisder resin having a terminal carboxyl group synthesized from a polyhydric alcohol, a polybasic acid, or an acid anhydride thereof! % polymerization degree of polylactone may be carried out. Add a polyester with carboxyl groups at both ends, lactones, a catalyst and a polyhydric alcohol of trihydric or higher valence, and react at a reaction temperature of 160°C to 230°C.
When reacted, first, open 1jA polymerization of lactones occurs, producing polylactone polyol. Then, a transesterification reaction occurs between the carboxyl terminals at both ends and the lactone chain, forming a polybasic acid/
A polyhydric alcohol/lactone random copolymer polyester is obtained.

As mentioned above, it is necessary to cause a sufficient transesterification reaction to form a random copolymer in order to synthesize a lactone-modified polynisdel polyol having a low melting point and good compatibility with solvents.

The molecular weight of the lactone river combined made in this way is usually 5.
It is about 00 to ioo, ooo. The molecular weight can be adjusted by determining the molecular weight of the polyester having carboxyl groups at both ends and the molar ratio of the polymerization initiator to the lactone.

(Effects of the Invention) The novel lactone polymer of the present invention can be used as a low shrinkage agent for unsaturated polyesters and epoxy resins, a surface modifier, a plasticizer for thermoplastic brass, a pigment dispersant, a urethane pigment dispersion improver, It can be extremely advantageously used in many fields such as a flexibility imparting agent for paints and a pigment dispersant.

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

In addition, in the examples, all parts indicate parts by weight.

Synthesis Example 1 In a four-eye flask equipped with a stirrer, a thermometer, a nitrogen gas introduction tube, and a condenser with a dehydration tube, 1095 parts of adipic acid,
1.767 parts of 6-hexanediol, 0. 002 parts and 140 parts under nitrogen atmosphere.
Dehydration begins at ℃, and as dehydration progresses, the temperature also increases to 220℃.
When the temperature was raised to ℃ and the reaction was allowed to proceed until the amount of dehydration reached 234 parts, the acid value (KOH1ull/Q) was 70.2.
A polyester having an average molecular weight (polystyrene equivalent) of MW-2480 was obtained.

Separately, in a similar apparatus, the polyester 30 obtained by the above reaction was
0 parts, ε-caprolactone 1677 parts, pentaerythritol 23 parts, and tetrabutyl titanate 0.02 parts and reacted at 210°C for 10 hours.
OHIglo) 1G, 3, water 1 base value (KOH■Q/
Q) 18.6, average molecule 1 (polystyrene equivalent)
A lactone polymer of MN-5760 was obtained.

Synthesis Example 2 111,392 parts of adipine, 954 parts of diethylene glycol, and 0.002 parts of tetrabutyl titanate were charged into a Yotsuro flask equipped with a stirrer, a Sa meter, a nitrogen gas inlet tube, and a condenser with a dehydration tube, and the mixture was heated from 140°C under a nitrogen atmosphere. Dehydration started, and as the dehydration progressed, the temperature rose to 220°C, and the reaction was allowed to proceed until the amount of dehydration reached 328 parts, resulting in a polyester with an acid value (KOHIMO) of 23.8 and an average molecular weight (in terms of polystyrene > MN = 6900). I got it.

Separately, in a similar apparatus, the polyester 82 obtained by the above reaction was
5 parts, C-caprolactone 4513 parts, pentaerythritol 102 parts, and tetrabutyl titanate 0.02 parts and reacted at 210°C for 10 hours.
(KOHu/a), water 1 [Ni1i (KO
A lactone polymer with HI (1/IJ), average molecular m<polystyrene equivalent) MN = 6240 was obtained.

Example 1 15 parts of unsaturated poly 1 silicate resin obtained from maleic anhydride and isophthalic acid and 1,2-propylene glycol, 1 part of t-butyl perbenzoate, M(101
1 part, 200 parts of calcium carbonate, and 4 parts of zinc stearate were mixed and stirred. Furthermore, from the paste, 1ff1 of glass fibers with a fiber length of 1 cm was made using a sheet mold compound machine.
A sheet material containing 100 parts was produced. After aging this at 40°C for 1 day, it was press-molded for 3 minutes at 150°C and 1100k Cl3 pressure to obtain a smooth plate with no uneven surface.

The linear shrinkage rate was 0.11% (expansion), and very good results were obtained.

Example 2 11t of unsaturated polyester wood similar to that used in Example 1
30 parts, 50 parts of styrene, tree 0820 obtained in Synthesis Example-2
1 part of t-butyl perbenzoate, 180 parts of calcium carbonate, 3 parts of M2O, and 3 parts of zinc stearate were mixed and stirred, and the kneaded paste was applied to a glass fiber mat so as to make 100 parts of glass fiber. The mixture was pressed to impregnate glass fibers and left at 40° C. for one day to obtain a sheet molding compound. Heat this to 140℃10
Press molding was performed for 4 minutes at 9/C13 to obtain a plate with a smooth surface and no warpage. Linear shrinkage rate is 0.132
% (expansion).

Claims (1)

[Claims] (1) It is characterized by consisting of a polyester resin having a terminal carboxyl group synthesized from a polyhydric alcohol, a polybasic acid, or an acid anhydride thereof, and a lactone polymer synthesized from lactones and a polyhydric alcohol of trihydric or higher valence. Low shrinkage agent.