JPS5950689B2 - Unsaturated polyester resin composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides an unsaturated polyester resin composition that requires a suitable amount of time for gelling during curing and molding, but requires a short time for curing after gelling. Regarding.

In recent years, the applications of unsaturated polyester resins, especially fiber-reinforced plastics, have been expanding.

In particular, unsaturated polyester resins containing curing catalysts, reinforcing fibers, etc., as well as thickeners such as calcium hydroxide and magnesium oxide, have excellent uniform moldability with glass fibers, etc. , sheet molding compound (SMC), bulk molding compound (BMC), etc., and are attracting attention as resin compositions for mold molding such as press molding and injection molding, and the demand for them is particularly increasing. However, since unsaturated polyester resins generally require a long time to cure and mold, the reality is that molded products using unsaturated polyester resins such as SMC are inferior in productivity.

By the way, in order to improve the productivity of molded products, it is necessary to shorten the time required for molding, but due to its properties and workability, it takes a certain amount of time for unsaturated polyester to gel (usually 1 to 5 minutes). It is preferable to shorten the time required from gelation to hardening as much as possible.

Various means have been proposed to shorten the time from gelation to hardening. One of these is that by adding a curing catalyst with a low half-life temperature to a curing catalyst with a high half-life temperature, the time from gelation to curing can be reduced compared to when a curing catalyst with a high half-life temperature is used alone. Attempts have been made to shorten the process, but in this case, there are drawbacks such as shortening the time until gelation due to curing catalysts with low half-life temperatures, and poor storage stability of the resin composition. It has been pointed out. From this point of view, the present inventors have conducted various studies and found that 1,1-bis(amylperoxy)3,3,5-trimethylcyclohexane (hereinafter abbreviated as A-1), or 1, If 1-bis(amylbaroxy)cyclohexane (hereinafter abbreviated as A-2) is blended into an unsaturated polyester resin composition as a curing catalyst and then cured and molded, the resin composition will gel. The time required for this process is appropriate (usually 1 to 5 minutes), and the time from gelation to curing is extremely short. It has been discovered that the above characteristics are better exhibited when used in combination with A-1 or A-2, and that the storage stability of the unsaturated polyester resin composition is not impaired by the addition of A-1 or A-2. We have now completed the present invention.

That is, the present invention relates to an unsaturated polyester resin composition containing an unsaturated polyester resin and A-1 or A-2 as a curing catalyst.

The unsaturated polyester resin used in the present invention is a mixture of unsaturated polyester and a crosslinking agent, and usually contains 80 to 20 parts by weight of the unsaturated polyester resin and 20 to 20 parts by weight of the crosslinking agent.
It consists of 80 parts by weight. Ethylenically unsaturated monomers (e.g., styrene, chlorostyrene, vinyltoluene, vinyl acetate, α-methylstyrene, diallyl phthalate, alkyl esters of acrylic acid, alkyl esters of methacrylic acid, etc.) are used as crosslinking agents. be done. Unsaturated polyester is produced by condensing, for example, an α,β monounsaturated dibasic acid and a polyhydric alcohol, if necessary in combination with a saturated dibasic acid;
Examples of β-monounsaturated dibasic acids include maleic acid, maleic anhydride, fumaric acid, and halogenated maleic anhydride; examples of saturated dibasic acids include phthalic acid, phthalic anhydride, halogenated phthalic anhydride, Examples include isophthalic acid, terephthalic acid, tetrahydrophthalic anhydride, succinic acid, adipic acid, and sebacic acid. Examples of the polyhydric alcohol include ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, and 1,3-butylene glycol. A as a curing catalyst used in the present invention
The 10-hour half-life temperatures of -1 and A-2 are 92°C and 93°C, respectively, and these are generally used alone or at 10 hours.
It is used in combination with a curing catalyst having a time half-life temperature of 45°C to 125°C. 10 used in combination with Λ-1 and A-2
Curing catalysts with a time half-life temperature of 45°C to 125°C 5 include 1,1-bis(t-butylperoxy)cyclohexane (B-2), 1,1-bis(t-butylperoxy)3, 3,5-trimethylcyclohexane (B-1
), t-butyl peroxyacetate, t-butyl peroxybenzoate (TBPB), t-butyl peroxy-2-ethylhexyl carbonate, di-t-butyl peroxy azela ate, peresters such as 2,5-dimethyl-2,5-dibenzoyl peroxyhexane, and the like.

When a curing catalyst is used in combination, A-1 or A-2 is blended in a proportion of usually 1 to 99%, preferably 10 to 90% of the total curing catalyst.

The amount of the curing agent in the resin composition of the present invention is usually 0.1 to 100 parts by weight per 100 parts by weight of the unsaturated polyester resin.
1.5 parts, preferably 0.6 to 1.0 parts.

The resin composition of the present invention may contain reinforcing fibers (e.g., glass fibers, chemical fibers, polycrystalline fibers, etc.), thickeners (e.g., magnesium oxide, finely divided silica, calcium hydroxide, etc.), and low-shrinkage agents (e.g., , polyethylene, polypropylene, etc.), optical fillers (e.g. calcium carbonate, clay,
talc, etc.) may be added. Preferred examples of the resin composition of the present invention include SMC. The resin composition of the present invention is molded by means known per se, particularly preferably by molding such as press molding or injection molding, and the curing temperature thereof is preferably 90 to 160°C. Examples 1-4, Comparative Examples 1-7 1. Preparation of SMC A resin composition was prepared having the following basic formulation and the type of curing catalyst and amount of benzoquinone as shown in Table 1.

Unsaturated polyester resin 100 parts [Polymer 6321 (manufactured by Takeda Pharmaceutical Co., Ltd.)] Calcium carbonate 100 parts Zinc stearate 3 parts Curing catalyst (as pure product) 1 part Magnesium oxide 1 part Chopped strand glass fiber (450g/Trl) ) 20 parts Benzoquinone 0 to 0.05 parts The obtained SMC was thickened at 40° C. for 2 days, and then subjected to a curing test and a storage stability test.

2. Curing Characteristic Values of SMC (1) Measuring Method Two SMC mats were placed on a press maintained at the temperature listed in Table 1, a thermoelectric body was sandwiched between them, and the curing heat generation curve was recorded on a recorder.

Curing time (CT): Time from 50°C to reaching maximum heat generation.

Gelation time (GT): Time from 50°C to reaching the inflection point of the curing exothermic curve.

Propagation time (PT): CT-GTO maximum exothermic temperature (PET): °C.

(2) Results: As shown in Table 1.

3. Storage stability of SMC SMC pine was stored in a constant temperature room at 40° C., and the number of days until a portion of it solidified was measured.

The results are shown in Table 2.

Claims (1)

[Claims] 1 as unsaturated polyester resin and curing catalyst 1,
An unsaturated polyester resin composition containing 1-bis(t-amylperoxy)3,3,5-trimethylcyclohexane or 1,1-bis(t-amylperoxy)cyclohexane.