JPH078945B2 - Low shrinkage agent for unsaturated polyester resin - Google Patents

Description

TECHNICAL FIELD The present invention relates to a shrinkage reducing agent for unsaturated polyester resins.

(Prior Art) An unsaturated polyester resin composition has a high dimensional shrinkage rate (for example, 10%) upon curing, and therefore, a molded product obtained from the resin by mold molding, injection molding, etc., may have distortion, cracks, sink marks, etc. However, there are drawbacks such as the occurrence of defects, lack of smoothness on the surface of the molded product, and embossing of the reinforcing fibers used for molding.

In order to eliminate these drawbacks, various studies have been conducted in recent years, and, for example, as shown in the invention disclosed in JP-A-48-34289, unsaturated polyester resin has polystyrene,
By mixing and curing an anti-shrinkage thermoplastic polymer such as polymethylmethacrylate, it is possible to produce a molded product having substantially no cure shrinkage, and the above-mentioned drawbacks are considerably improved. Has become.

(Problems to be Solved by the Invention) However, ordinary polystyrene, polymethylmethacrylate, and other anti-shrinkage plastic polymers have low dispersion stability in the unsaturated polyester resin composition, and the mixture is kept for a while (1 to 1). When left standing for 5 hours, the polymer has a drawback that it floats on the upper part of the composition, and it has a drawback that it is poorly compatible with fillers and other inorganic fillers and has poor dispersibility.

As a solution to these drawbacks, a shrinkage reducing agent composed of a lactone polymer having various terminal groups has been proposed.

However, lactone polymers with high crystallinity have poor solubility in the styrene monomer used at the same time when used as a shrinkage reducing agent, and when carbon black is used as a pigment to make a black molded product, the surface of the molded product is Had a drawback that it turned white.

As a result of diligent studies by the present inventors to improve this drawback,
Oxycarboxylic acid of fatty acid, polyhydric alcohol and aromatic polybasic acid or an ester compound consisting of its acid anhydride are reacted at a certain ratio, and ε-caprolactone is reacted with this to give a lactone polymer, thereby converting styrene to styrene. The inventors have found that when a black molded product having improved solubility and using carbon black as a pigment is used, a molded product with less whitening phenomenon can be obtained and a good molded product with almost no shrinkage can be obtained.

(Structure of the Invention) That is, the present invention is: a) 50 to 90% by weight of an aliphatic oxycarboxylic acid b) 10 to 50% by weight of an ester of a polyhydric alcohol and an aromatic polybasic acid or an anhydride thereof c) The above a ) And b) in a total amount of 10 to 40% by weight, 90 to 60% by weight of ε-caprolactone, and a lactone polymer having an average molecular weight of 10,000 to 10,000. Shrinking agent ".

As the aliphatic oxycarboxylic acid which is the component a) used in the present invention, glycolic acid, oxycaproic acid, 12-hydroxystearic acid and hydroxypivalic acid are preferable,
Further, oxycarboxylic acid described in the present invention includes -OH, -COO.
It also includes an aliphatic polyhydric alcohol having a structure having one H and an aliphatic polybasic acid or a monoester of an anhydride thereof.

The aliphatic polyhydric alcohol in this case is ethylene glycol, diethylene glycol, 1,3 propanediol, 1,4
-Butylene diol, 1,5 pentane diol, 1,6 hexane diol, 1,2 propylene glycol, 1,3-butylene glycol, neopentyl glycol, hydroxypivalic acid ester of neopentyl glycol, 2-methyl-1,
It is possible to use 3 propanediol, 2,3,5-trimethylpentanediol, trimethylolpropane, trimethylolethane and the like.

As the aliphatic polybasic acid or its anhydride, succinic acid,
There are maleic acid, fumaric acid, adipic acid, sebacic acid, azelaic acid, dodecane diacid, succinic anhydride, maleic anhydride and the like, and these can be used together.

The polyhydric alcohol used in the ester of the polyhydric alcohol and the aromatic polybasic acid or its acid anhydride as the component b) of the present invention are ethylene glycol, diethylene glycol, 1,3 propanediol and 1,4-butylene. Diol, 1,
5 pentanediol, 1,6 hexanediol, 1,2 propylene glycol, 1,3-butylene glycol, neopentine glycol, hydroxypivalic acid ester of neopentyl glycol, 2-methyl-1,3 propanediol, 2,
3,5-Trimethylpentanediol, trimethylolpropane, trimethylolethane, etc. can be used.

As the aromatic polybasic acid or its anhydride, phthalic acid, isophthalic acid, terephthalic acid, trimellitic acid, pyromellitic acid or their anhydrides can be used.

[Epsilon] -caprolactone which is the component c) of the present invention is industrially manufactured and commercially available by oxidizing cyclohexanone with a peracid such as hydrogen peroxide or peracetic acid by the Bayer-Billiker reaction.

In the present invention, it is necessary that 60-90% by weight of ε-caprolactone is contained in the resin as the shrinkage reducing agent.

When the content of ε-caprolactone is less than 60% by weight, the effect as a shrinkage reducing agent is not exerted, and when it is more than 90% by weight, the compatibility with styrene becomes poor due to the crystallinity of polycaprolactone.

The charging ratio of the ester of oxycarboxylic acid / polyhydric alcohol and aromatic polybasic acid or anhydride thereof is 5/5 to 9: the ester of oxycarboxylic acid / polyhydric alcohol and aromatic polybasic acid or anhydride thereof. It must be / 1 (weight ratio).

The charging ratio of the ester of oxycarboxylic acid / polyhydric alcohol and aromatic polybasic acid or its anhydride is 50% or less of the ester of polyhydric alcohol and aromatic polybasic acid or its anhydride with respect to oxycarboxylic acid. Does not exhibit the effect as a shrinkage reducing agent, and when it exceeds 90%, whitening phenomenon occurs when carbon black is used as a pigment to make a black product, which impairs commercial properties.

Here, the synthesis of an ester of a polyhydric alcohol and an aromatic polybasic acid or its anhydride is performed as follows.

0.8-1.2% phthalic anhydride for diethylene glycol
12 times when the reaction temperature was raised by charging a double volume reaction flask.
Phthalic anhydride, which was flaky at 0 to 130 ° C, and diethylene glycol melt, and the reaction begins.

The reaction temperature is further slowly raised to 150-170 ° C. over 2-3 hours.

Rapid heating is not preferable because the reaction temperature may exceed 200 ° C due to the reaction heat of phthalic anhydride, and the product may be colored.

The reaction temperature is maintained at 150 to 170 ° C and the reaction is continued for 4 to 6 hours.

At the end point of the reaction, the concentration of diethylene glycol in the reaction solution is measured using a gas chromatograph, and the remaining amount is quantified to terminate the reaction when the concentration of diethylene glycol is in the range of 17 to 32%.

If the concentration of diethylene glycol is lower than 21%, the esterification reaction will proceed too much and dehydration will start.

Further, if it exceeds 24%, unreacted phthalic anhydride remains, which is not preferable.

In the present invention, ring-opened oxycaproic acid can be used instead of ε-caprolactone which is the component C).

Also, other lactones can be copolymerized.

Next, a method for synthesizing the lactone polymer which is the shrinkage reducing agent of the present invention will be described.

The most basic method is to first synthesize a polyhydric alcohol and an aromatic polybasic acid to prepare a monoester or polyester polyol which is a component b) of a terminal hydroxyl group or a terminal carboxylic acid, and then add an aliphatic oxy group a) as a component. carboxylic acid,
A predetermined amount of ε-caprolactone which is the component c) is charged and ring-opening polymerization is performed to synthesize a lactone polymer.

Furthermore, it can be synthesized by simultaneously charging and reacting oxycarboxylic acid, polyhydric alcohol, aromatic polybasic acid, and ε-caprolactone.

The reaction temperature is 130 to 240 ° C, preferably 140 to 230 ° C.

In addition, passing an inert gas during the reaction gives good results on the hue of the resin.

In this reaction, titanium compounds such as tetrabutyl titanate and tetrapropyl titanate are used as a caprolactone ring-opening reaction catalyst, dibutyltin laurate, tin octylate, dibutyltin oxide, stannous chloride and stannous bromide.
0.01 to 50 ppm of tin, stannous iodide, etc., especially 0.1 to 10 pp
It is preferable to use m.

Further, among these catalysts, particularly titanium compounds show sufficient catalytic activity for transesterification reaction.

The average molecular weight of the lactone polymer thus obtained is
It is 1000 to 10000.

If it is less than 1000, the effect as a low-contracting agent is not sufficient, and if it is more than 10,000, the viscosity is high, which is disadvantageous when it is mixed with a curable resin.

The molecular weight can be adjusted by adjusting the reaction molar ratio of the polyester polyol synthesized from the components a) and b) and ε-caprolactone.

The unsaturated polyester resin used with the shrinkage-reducing agent of the present invention is produced from α, β-unsaturated dibasic acid and glycols, or, if necessary, by further using a saturated dibasic acid in combination.

As the α, β-unsaturated dibasic acid, maleic anhydride, maleic acid, fumaric acid, mesaconic acid, tetraconic acid, itaconic acid, chlorinated maleic acid and the like are used.

As saturated dibasic acid, orthophthalic acid, phthalic anhydride,
Isophthalic acid, terephthalic acid, tetrahydrophthalic acid,
Halogenated phthalic anhydride, etc. are mentioned, and these esters etc. are also used.

As glycols, ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, butylene glycol, neopentyl glycol, hexalen glycol, hydrogenated bisphenol A, 2,
2-di- (4-hydroxypropoxyphenyl) propane, ethylenoxide, propylenoxide and the like are useful.

If the proportion of α, β-unsaturated dibasic acid in the component is less than 50 mol%, the desired low shrinkage effect cannot be sufficiently obtained, and therefore α, β-unsaturated dibasic acid is 50-100. It should be mol%, especially in the case of sheet molding compounds, 100% is better.

For the production of the unsaturated polyester, known production methods such as a dissolution method, a solution method and an epoxy method are used.

Unsaturated polyester has a molecular weight of 1,000 to 3,000 and an acid value of 10 to 5
Those having a hydroxyl value of 0 and a hydroxyl value of 5 to 60 are preferable.

The shrinkage reducing agent of the present invention is usually used by adding an unsaturated monomer having at least one ethylenic double bond in one molecule together with the unsaturated polyester resin.

The unsaturated monomer must be one that can react with the unsaturated polyester to be crosslinked and heat-cured, and one that dissolves the unsaturated polyester is preferable.

Specific unsaturated monomers include, for example, styrene, vinyltoluene, lower alkyl esters of acrylic acid or methacrylic acid (eg, methyl methacrylate, methyl acrylate, ethyl methacrylate, ethyl acrylate, propyl methacrylate, acrylic acid). Propyl, butyl methacrylate, butyl acrylate, 2-ethylhexyl methacrylate, 2-ethylhexyl allylate), methacrylic acid, acrylic acid, divinylbenzene, chlorostyrene, α-methylstyrene, diarylphthalate, ethylene glycol dimethacrylate, trimethylol Propane trimethacrylate, 2,5-dichlorostyrene,
2.5-Dibromostyrene, pentabromophenol allyl ether, tribromophenyl acrylate, dialkylphosphonic acid, antimonytrialoxide, diallylbenzenephosphonate, tricresyl phosphate, triallyl phosphate, diallyl ethyl phosphate, β- Methyl (methylethyl) phosphonoacrylate, (diallylphosphonomethyl) ether and the like can be mentioned, but styrene is mainly used.

Of course, these monomers are not only 1 type, but 2
Mixtures of more than one can also be used.

When the shrinkage-reducing agent of the present invention is used together with the unsaturated polyester resin or the like, an inorganic filler can be usually used together.

Examples of the inorganic filler include metal oxides such as silica, alumina, iron oxide, zinc oxide and magnesium oxide: metal hydroxides such as aluminum hydroxide, magnesium hydroxide and iron hydroxide: iron powder, aluminum powder and the like. Metal powder: Others include asbestos powder, glass powder, calcium carbonate, magnesium carbonate, sodium sulfate, diatomaceous earth, etc. (fiber length 3
~ 25mm chopped sland and fiberglass mats are excluded).

The particle size is 0.1-100 μm, preferably 30 μm or less.

Further, among these, particularly when a metal hydroxide is used, there is an advantage that the viscosity of the resin composition is low.

When the shrinkage-reducing agent of the present invention is used together with the unsaturated polyester resin or the like, it is usually possible to use a reinforcing material in addition to the inorganic filler.

Examples of the reinforcing material include glass fiber, carbon fiber, asbestos, potassium titanate, whiskers and metal fibers.
A fiber having a fiber length of 3 to 25 mm is used.

When the shrinkage reducing agent of the present invention is used together with the unsaturated polyester resin or the like, a polymerization initiator is usually used. Further, as the polymerization initiator, benzoyl peroxide, lauryl peroxide, methyl ethyl ketone peroxide, dicumyl peroxide, 2,5-di (peroxybenzoate) hexyne-3, tert-butyl perbenzoate and other organic peroxides, Azo compounds such as azobisisobutyronitrile and dimethylazodiisobutyronitrile can be used.

Next, the composition of each component will be described.

30-80 parts by weight of unsaturated polyester and 70-20 parts by weight of ethylenically unsaturated monomer, but unsaturated polyester +
100 parts by weight of the ethylenically unsaturated monomer is used.

When the unsaturated polyester is 30 parts by weight or less, the cured product cannot have practical strength.

On the other hand, if the amount exceeds 80 parts by weight, the viscosity becomes high and handling becomes difficult, and the strength becomes weak.

The lactone polymer in the low-shrinking agent for unsaturated polyester resins of the present invention, which is a low-shrinking agent, is 5 per 100 parts by weight of the total of the unsaturated polyester and the ethylenically unsaturated monomer.
~ 200 parts by weight, preferably 10 to 100 parts by weight.

If it is less than 5 parts by weight, the effect of low shrinkage is insufficient.

If the amount is more than 200 parts by weight, the mechanical strength of the cured product will decrease.

The inorganic filler is 40 to 400 parts by weight, preferably 40 to 400 parts by weight, based on 100 parts by weight of the unsaturated polyester and the ethylenically unsaturated monomer.
It is used in a proportion of 50 to 300 parts by weight.

If it is less than 40 parts by weight, the effect of preventing uneven coloring is not obtained.

Further, if it exceeds 400 parts by weight, the mechanical strength of the obtained cured product is not practical.

The reinforcing material is 10 to 200 parts by weight, preferably 30 to 100 parts by weight based on 100 parts by weight of the unsaturated polyester and the ethylenically unsaturated monomer.
Used at a rate of 100 parts by weight.

If it is less than 10 parts by weight, there is no strengthening effect, and if it exceeds 200 parts by weight, the strength of the obtained cured product becomes rather low.

A proper amount of polymerization initiator, generally 0.01 to 5 unsaturated polyester
It is used in an amount of 0.5% by weight, preferably 0.5 to 2% by weight.

In addition to these components, silane coupling agents, silane coupling accelerators, aggregation inhibitors, polymerization inhibitors, thickeners,
You may mix | blend a pigment, a lubricant, etc.

To prepare the resin composition of the present invention, a commercially available polyester resin containing an unsaturated polyester and an ethylenically unsaturated monomer is mixed with a lactone polymer, an inorganic filler, a reinforcing material and a polymerization initiator at the same time. May be.

(Effects of the Invention) (a) The lactone polymer, which is a low-contracting agent for unsaturated polyester resins of the present invention, is a surface modifier of unsaturated polyester or epoxy resin, a plasticizer of thermoplastics,
It can be used extremely advantageously in many fields such as a pigment dispersant, a urethane pigment dispersibility improver, a paint flexibility imparting agent, and a pigment dispersant.

(B) The unsaturated polyester resin composition containing the shrinkage-reducing agent of the present invention thus prepared is excellent in storage stability and has a shrinkage ratio of about +0.05 to + 0.1% (expansion).
Thus, it is possible to give a smooth cured product without uneven coloring.

Next, the present invention will be described with reference to synthesis examples and examples.
The present invention is not limited to these.

In the examples, all parts are parts by weight.

Synthesis Example 1 A four-necked flask equipped with a nitrogen inlet tube, a thermometer, a condenser for removing esterified water and a stirrer was charged with 530 parts of diethylene glycol and 740 parts of phthalic anhydride, and reacted at 140 ° C to 160 ° C for 3 hours to obtain an acid. Value 178
KHOmg / g, hydroxyl value 144KHOmg / g (units are omitted below)
The polyester polyol of was obtained.

Synthesis Example 2 554 parts of the polyester polyol obtained in Synthesis Example 1, 830 parts of 12-hydroxystearic acid, ε-caprolactone 7840
And 0.01 part of tetrabutyl titanate were charged in the same apparatus as in Synthesis Example 1 and reacted at 180 ° C. for 7 hours to obtain a lactone polymer having an acid value of 24.2, a hydroxyl value of 23.5 and a melting point of 46 to 47 ° C.

Synthesis Example 3 Diethylene glycol 197.2 was placed in the same apparatus as in Synthesis Example 1.
Parts, phthalic anhydride 275.3 parts, 12-hydroxystearic acid 1102.5 parts, ε-caprolactone 8925 parts, tetrabutyl titanate 0.1 parts, and reacted at 180 ° C. for 7 hours to give an acid value of 25.4, a hydroxyl value of 23.2 and a melting point of 46. ~ 47 lactone polymers were obtained.

Example 1 55 parts of unsaturated polyester resin obtained from maleic anhydride and 1.2-propylene glycol, 45 parts of styrene,
After kneading 50 parts of the resin obtained in Synthesis Example-2, 1 part of t-butylperpenzoate, 1 part of Mgo, 120 parts of calcium carbonate, 2 parts of carbon black as a pigment, and 80 parts of glass fiber having a fiber length of 1 cm with a kneader, The mixture was aged at 40 ° C for one day to obtain a bulk molding compound.

This was injection-molded at 150 ° C. and a pressure of 100 kg / cm ² for 3 minutes to obtain a molded product having a uniform surface.

Molding shrinkage is 0.08 (%) of expansion Surface gloss 60 degrees Reflectivity 80
~ 90%, good results of hue black were obtained.

Example 2 Unsaturated polyester resin 60 similar to that used in Example 1
Parts, styrene 40 parts, resin 30 obtained in Synthesis Example-3, t-butyl perhenzoate 1 part, aluminum hydroxide 100
Parts, 1 part of Mgo, 3 parts of zinc stearate, and 2 parts of carbon black were kneaded with 80 parts of 1 cm long glass fiber with a kneader, and then aged at 40 ° C. for 1 day to obtain a bulk molding compound.

When this was transfer-molded at 150 ° C. and a pressure of 100 kg / cm ² for 3 minutes, a molded product having a uniform surface was obtained.

Molding shrinkage is expansion 0.08 (%) Surface gloss 60 degrees Reflectivity 80 ~
90%, good result of hue black was obtained.

Claims (1)

[Claims] 1. A) 50 to 90% by weight of an aliphatic oxycarboxylic acid b) 10 to 50% by weight of an ester of a polyhydric alcohol with an aromatic polybasic acid or an anhydride thereof c) Of the above a) and b) A low-shrinkage agent for unsaturated polyester resins, which comprises 90 to 60% by weight of ε-caprolactone based on a total amount of 10 to 40% by weight and a lactone polymer having an average molecular weight of 1,000 to 10,000.