JPH0476006A - Peroxide composition excellent in safety and stability - Google Patents

Abstract

PURPOSE:To obtain a peroxide composition excellent in stability and safety during storage in spite of its high active oxygen content by mixing tert. butyl peroxyisopropyl carbonate with a peroxyketal in a specified ratio. CONSTITUTION:45-85wt.% tert. butyl peroxyisopropyl carbonate is mixed with 55-15wt.% peroxyketal of the formula (wherein R' is ethyl or propyl when R is H; and R' is methyl, ethyl or propyl when R is methyl) [e.g. 1,1-bis(tert. amylperoxy)-cyclohexane] to obtain a peroxide composition of an active oxygen content of 8.6% or above. This composition has a property that it has markedly improved storage stability, and its power of explosion is markedly lowered, can shorten the curing time of a molding such as SMC or BMC without detriment to its flow, is useful to shorten the molding cycle, can prolong the pot life and shelf life of a molding material and can give a molding of an excellent surface appearance.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a peroxide composition that is useful for unsaturated polyester resin or vinyl ester resin molding materials and has excellent safety and stability.

<Prior art> FRP molding materials such as SMC and BMC are made by adding thickeners, curing agents, and unsaturated polyester resins or vinyl ester resins.
After mixing a curing accelerator, a reinforcing agent, a filler, a low-shrinkage agent, a mold release agent, an inhibitor, and a vinyl monomer, the mixture is shaped into a sheet, pellet, or bulk. Since these molding materials are suitable for mass production, they are hardened and molded using various molding methods such as compression, transfer, and injection, and are now widely used industrially for automobile parts, electrical parts, housing materials, etc.

The curing agent used in the molding material affects the flow characteristics and curing completion time of the molding material during press molding, and the surface appearance characteristics of the molded product such as gloss, smoothness, and colorability. The choice is important as it has a major impact on shelf life and pot life.1. In consideration of productivity, molding is generally carried out at a high temperature of 120 to 160°C, so various peroxides and azo compounds that decompose at such temperatures can be used as curing agents, but the total Well-balanced t-butyl peroxybenzoate is the most widely used.

However, recently, FRP molding has become popular because the initial investment cost is low and the design is flexible. Demand is increasing as it is being reconsidered as a medium-volume production method for automobile parts, electrical parts, housing equipment, etc. in place of steel sheet press forming. Along with this,
Mechanization and automation of processes before and after press forming, such as the development of high-speed presses and automatic SMC charging machines, have progressed to improve productivity by shortening the forming cycle. Naturally, there has been a strong demand for curing agents that have a long pot life or shelf life, and that can maintain the flow time of SMC as long as possible to shorten the time from the start to the end of curing (fast curing). T-butyl peroxybenzoate does not meet this need.

-Therefore, the development of curing agents to replace t-butyl peroxybenzoate has become active. Various curing agents and curing systems have been proposed (V, R, Kamath,
R, B, Gallagher, Plastics Compounding
ng), Volume 4, No. 6, pp. 41-44, 1981)
Among these, t-butylperoxyisopropyl carbonate has become popular among molding material manufacturers and is attracting attention because it can be cured quickly without impairing the characteristics of t-butylperoxybenzoate.

t-Butylperoxyisopropyl carbonate is a curing agent that cures quickly and has excellent surface appearance properties for molded products, but its biggest drawback is that it is highly dangerous (lack of safety and stability during storage). Organic peroxides inherently have the risk of fire and explosion, but among them, t-butylperoxyisopropyl carbonate is a particularly dangerous category due to its high amount of active oxygen, and should not be handled. Therefore, high-purity products are usually avoided and are commercially available and used as 75% diluted products.However, dilution with a solvent only reduces the curing activity due to a decrease in the active ingredient. Moreover, it is undesirable because it adversely affects the curing properties and the surface appearance characteristics of the molded article, and is often seen as a fatal drawback in curing unsaturated polyester resins or vinyl ester resins in which a large amount of curing agent is added.

On the other hand, as the amount of curing agent used and handled increases,
Molding material manufacturers are also becoming increasingly aware of the storage and handling of dangerous organic peroxides. Demand for curing agents that have superior curing performance as well as safety and stability is increasing year by year. In addition, the amount of active oxygen in a curing agent indicates the amount of active ingredients, and a high amount of active oxygen indicates excellent solubility between the curing agent and the resin and compatibility between the curing agent fragments and the molded product. It is preferable in terms of physical properties of molded products. However, in general, the higher the amount of active oxygen, the higher the risk. Furthermore, the faster the curing (the faster the curing rate), the worse the stability during storage, and it is extremely difficult to develop a curing agent that satisfies these contradictory conditions.

For example, JP-A-1-233269 describes a peroxide composition consisting of t-butylperoxybenzoate and t-butylperoxyisopropyl carbonate, but it is still insufficient in terms of curing properties, safety, and stability. It's not satisfactory (, also J, R, K
olczynski and G. A. Harpel.
At the 28th SPI Annual Meeting 1-D (1973), t-butyl peroxyisopropyl carbonate and t-
-'butyl peroxyoctoate has been reported, but it is significantly lacking in stability during storage. -1 <Problem to be solved by the invention> Therefore, in practical terms, it satisfies the curing performance and molded product quality equivalent to or higher than that of butylperoxyisopropyl carbonate,
And, there is a strong need for a hard carbonaceous acid having equivalent quantum safety and stability to t-butylperoxybenzoyl.

<Means for Solving the Problems> As a result of extensive research in order to meet the above-mentioned needs, the present inventors have discovered that rubilveroxyisobrobyl carbonate-1.
It has been found that a composition containing a specific proportion of 3-gishketal has excellent properties, and the present invention has been accomplished based on this finding. That is, the present invention provides 45 to 85 d% by weight of t-bugol peroxyisobrobyl carbonate-1 and 55 to 15% by weight of the former (wherein, when one hydrogen atom, Ro is ethyl and propyl groups, and when [ku is a megyl group, R'iJ
This peroxide composition is composed of peroxyketals represented by IA (methyl, ethyl, and propyl groups), has 31 bubbling agents, and has an active oxygen content of 86% or more. Despite having a high amount of active oxygen, it has excellent stability and safety during storage, and SMC,
It has excellent performance as a curing agent for molding materials such as BMC.

The t-bug ruboroxyisopropyl carbonate used in the present invention can be produced by a known method by reacting isobrobyl chloroform-1. with t-butyl hydroperoxide in the presence of an alkali. Further, as the peroxyketal, 1,1-bis(t-amylperoxy)cyclohexane, 1,1-bis(t-
hexylyloxy)cyclohexane; 1. ]-Bis(
t-butylperoxy)-3,3,5-1-rimedylcyclohexane; 1,1-bis(t-amylperoxy)
-3,3,5-trimethylcyclohexane; 1,1-bis(t-hexylperoxy) -3,3,5-trimethylcyclohexane, etc., and the corresponding cyclic ketone in the presence of an acidic catalyst It can be produced by a known method by reacting with t-alkyl hydroperoxide.

Table 1 shows the amount of active oxygen, ballistic mortar value (Trinny 1 Heguchi I・Relative value to luene)
100° showing the decomposition explosive power and thermal decomposition characteristics shown by
Indicates the half-life value and storage stability at C. 1 self-accelerated decomposition temperature.

Table 1 Next, methods for measuring each of the above characteristics will be explained.

Half-life, 0.1 mol/℃ The decomposition in a benzene solution was tracked by the change in the amount of active oxygen, and the initial half of the amount of active oxygen was
I sought it as a time to become.

Active oxygen amount: represents the concentration of peroxide groups in the sample,
It was determined by iodometry using a ferric chloride solution.

Load 10g of the sample into the decomposition explosive crab bullet mortar tester, and
The power of trinitrotoluene is reduced to 1 by decomposing it with a detonator.
It represents the explosive power of the sample when it is set to 00. You can know the relative explosive power when a large amount of peroxide decomposes, and the higher the number, the more dangerous it is.

Self-accelerated decomposition temperature: Determined according to the BAM method.
The temperature was determined as the lowest temperature at which self-accelerated decomposition occurs within 7 days when a sample of 100 mn was placed in the chamber and the set temperature was changed in 5°C increments.

The storage temperature is 30°C lower than this temperature.
``C low temperature is a guideline for handling temperature.

Table 1 shows that the decomposition and explosive power of t-butylperoxyisopropyl carbonate is very high compared to the amount of active oxygen, and for peroxyketal, the value of the amount of active oxygen is large (as the value of the decomposition and explosion increases). In terms of thermal decomposition properties, both t-butylperoxyisopropyl carbonate and peroxyketal are more easily decomposed than t-butylperoxybenzoate in terms of half-life; A comparison of oxyisopropyl carbonate and peroxyketal shows that the latter is about f3 times faster than the former, but the self-accelerated decomposition temperature is higher for peroxyketal, indicating that it is difficult to decompose. This indicates that the thermal decomposition behavior (mechanism) of t-butyl peroxyisopropyl carbonate and peroxyketal is significantly different. However, since both are liquids, they can be easily mixed by simply mixing them, and the mixing ratio is 45 to 85 t-butylperoxyisopropyl carbonate.
The amount of peroxyketal is 55 to 15% by weight, and the amount of active oxygen is 8.6% or more, preferably 50 to 80% by weight of the former and 50 to 20% by weight of the latter. If the amount of peroxyketal exceeds 55% by weight, problems will arise in the curing performance such as the surface appearance characteristics of the molded product, and if it is less than 15% by weight, the composition may not be fully satisfactory in terms of safety and stability. I can't get it. The amount of active oxygen is 8
．． If it is less than 6%, problems will occur due to a decrease in the amount of active ingredients in the curing agent.

The unsaturated polyester resin referred to in the present invention is a reaction product obtained by a heating dehydration condensation reaction with glycols, which always contains an unsaturated dibasic acid as one component, and if necessary, in combination with a saturated dibasic acid. Vinyl ester resin is obtained by diluting with polyepoxide and α,β-
It is obtained by diluting an unsaturated base acid equivalent reactant with a vinyl monomer. The present invention can be applied to resins commonly called radical-curable thermosetting resins.

The invention consists of mixing two types of peroxides in specific ratios, which do not differ significantly in their rate of thermal decomposition but differ significantly in their thermal decomposition mechanisms. Therefore, the interaction between the radically active species generated by the decomposition of one peroxide and the radically active species generated by the decomposition of the other peroxide produces excellent characteristics that cannot be expected from the properties of the two alone. It seems that it was completed.

<Effects of the Invention> Since the present invention is configured as described above, the peroxide composition has (1) significantly improved stability during storage, and (2) significantly reduced power when decomposed and exploded. When used in molding materials such as SMC and BMC, (3) it can shorten the curing time while maintaining the flow characteristics of the molding material, which helps shorten the molding cycle; 4) The pot life and shelf life of the molding material can be extended, and (5) a molded product with excellent surface appearance characteristics can be obtained.

<Examples> The present invention will be explained below with reference to Examples, Comparative Examples, and Reference Examples, but these are for illustrative purposes only and are not intended to limit the present invention.

Examples 1 to 5 Peroxide compositions of the present invention were produced by varying the amounts and types of t-butylperoxyisopropyl carbonate and peroxyketal, and the amount of active oxygen, decomposition explosive power, and self The accelerated decomposition temperature was measured.

Next, each composition was used as a curing agent to prepare an unsaturated polyester resin (Polymer B manufactured by Takeda Pharmaceutical Co., Ltd.) for housing SMC.
), JIS K-6901 using 1% by weight
A heat curing test and a pot life measurement experiment were conducted using a method similar to the above, and the gelation time, curing time, and pot life were measured.

Next, a molded article was produced from an unsaturated polyester resin using the perforation resistance 1 to 1 of the present invention as a curing agent, and the surface characteristics of the molded article were examined.

Namely, 70 parts of unsaturated polyester resin (Polylite PS-260 manufactured by Inu Nippon Ink Co., Ltd.), 30 parts of a low shrinkage agent (Modipar 3 VIOB30 manufactured by Ippon Yushi Co., Ltd.), 6 parts of curved lead stearate, and calcium carbonate. 1 part of the perogizide composition of the present invention was added to 130 parts of magnesium oxide and 1 part of magnesium oxide, and the mixture was mixed sufficiently uniformly using a /hi mixer to adjust the dope. This taupe pour,
A sheet was created by impregnating the mat. This was thickened in a constant temperature room at 40° C. for 48 hours to obtain an SMC molding material. Molded for 6 hours at a molding temperature of 145°C, J, 2
A molded product of 0×120×3 mm was obtained, and the surface tm condition was visually observed to determine the appearance characteristics.

The composition and measurement results of the Burogisard composition are shown in Table 2.

In the figure, 0: Very good surface gloss - 00 Good surface gloss;
△・Blooming occurs on the surface and the gloss is poor.

Comparative Examples 1 to 9 Next, the ratio of t-butylperoxyisopropyl carbonate to peroxyketal was determined for compositions other than the present invention, as well as for typical conventionally used compositions and curing agents. The decomposition explosive power, self-accelerated decomposition temperature, curing characteristics, pot life, and surface appearance characteristics of the molded products were investigated.

The results are shown in Table 2. In the properties of t-butyl peroxyisopropyl carbonate and t-butyl peroxybenzoate, the parentheses indicate the values shown in Table 1.

■5 As is clear from Table 2, the composition of the present invention has a longer bot life than the conventional compositions, 1-butylperoxyisopropyl carbonate and t-butylperoxybenzoate (Comparative Example 4) , t-bugol baroxy, isopropyl carbonate 1~ and t-butylperoxybenzoate have a longer bot life and a faster curing speed (Comparative Example 5), and t-butylperoxybenzoate-1. Compared to 1.1-bis(1-hexylperoxy)cyclohexane, the curing speed is faster (Comparative Example 6) and the surface properties are better (Comparative Example 6). It can be seen that the bot life is longer ((Comparative Example 7) and the surface properties are better than that of 3,3.5-trimedyl hexane and t-butyl peroxyoctoate (Comparative Example 7). In the composition of the present invention, if the content of 1゜1-bis(t-hexylperoxy)cyclohexylnone exceeds 50%, the surface properties of the molded product will be significantly reduced (Comparative Example 1). It has a longer pot life and faster curing than butyl baroxy isopropyl carbonate (Comparative Example 8), and has a significantly faster curing speed than a 75% solvent diluted product ((Comparative Example 3) and has excellent surface properties. is good (Comparative Example 3).

As shown in the above Examples and Comparative Examples (the composition of the present invention has t-butylperoxyisopropyl carbonate
・The safety and stability are significantly improved compared to t-
It can be seen that the curing properties are equivalent to or higher than that of butyl peroxybenzoate, and that it has excellent curing properties.

Claims (1)

[Claims] 45 to 85% by weight of t-butylperoxyisopropyl carbonate and 55 to 15% by weight of the general formula ▲ There are numerical formulas, chemical formulas, tables, etc. ▼ (In the formula, when R is a hydrogen atom, R ' is an ethyl and propyl group, and when R is a methyl group, R' is methyl,
A peroxide composition having excellent safety and stability, which contains a peroxyketal represented by ethyl and propyl groups, and has an active oxygen amount of 8.6% or more.