JP2833168B2 - Peroxide composition with excellent safety and stability - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a peroiside composition which is useful for an unsaturated polyester resin or vinyl ester resin molding material and is excellent in safety and stability.

<Conventional technology> For FRP molding materials such as SMC and BMC, thickening agents, curing agents, curing accelerators, reinforcing agents, fillers, low shrinkage agents, release agents, and banned unsaturated polyester resins or vinyl ester resins After mixing the agent and the vinyl-type monomer, the mixture is formed into a sheet, pellet, or bulk, respectively. Since these molding materials are suitable for mass production, they are cured and molded by various molding methods such as compression, transfer, and injection, and are now widely used industrially as automobile parts, electric parts, and housing materials. . The curing agent used in the molding material is used for the flow characteristics and curing end time of the molding material at the time of press molding, the glossiness of the molded product, the smoothness, the surface appearance characteristics such as coloring, and the molding material. It has a significant impact on shelf life and pot life, and the choice is important. In consideration of productivity, since molding is generally performed at a high temperature of 120 to 160 ° C., various peroxides and azo compounds that decompose at such a temperature can be used as a curing agent. Balanced t-butyl peroxybenzoate is most widely used.

However, recently, FRP molding has been reviewed as a medium-volume production method for automotive parts, electric parts, housing equipment, etc., replacing steel plate press molding because of the low initial investment cost and free design, and the importance is increasing. doing. Along with this, the development of high-speed presses aimed at improving productivity by shortening the molding cycle and the mechanization and automation of processes before and after press molding such as automatic SMC charging machines have been advanced. Naturally, there has been a strong demand for a (fast curing) curing agent which has a long pot life or shelf life and can keep the flow time of the SMC as long as possible to shorten the time from the start to the end of curing. t-Butyl peroxybenzoate does not meet this need. Therefore, the development of a curing agent for replacing t-butyl peroxybenzoate has been active. Various curing agents and curing systems have been proposed (VRKamath, RBG
allagher, Plastics Compounding (Plastic
s Compounding), Vol. 4, No. 6, pp. 41-44, 1981
T), t-butyl peroxyisopropyl carbonate has gained attention among molding material manufacturers as a material which can be rapidly cured without impairing the characteristics of t-butyl peroxybenzoate.

t-butyl peroxyisopropyl carbonate is
Although the curing agent is fast-curing and has excellent surface appearance characteristics of molded articles, its greatest disadvantage is that it is dangerous and lacks safety and stability during storage. Organic peroxides inherently have a risk of fire and explosion. Among them, t-butyl peroxyisopropyl carbonate has a high amount of active oxygen, and thus belongs to a particularly dangerous category, and is not sufficiently handled. Attention is needed. Therefore, high-purity products are usually avoided and they are marketed and used as 75% diluted products. However, dilution with a solvent not only decreases the curing activity due to the decrease in the active ingredient, but also adversely affects the curing characteristics and the surface appearance characteristics of the molded product, which is not preferable. There are many cases where fatal defects occur in curing.

On the other hand, as the usage amount and the handling amount of the curing agent increase, the molding material manufacturers are increasingly aware of the storage and handling of dangerous organic peroxides. As with the curing performance, there is a growing demand for a curing agent that is more secure and more stable. Although the amount of active oxygen of the curing agent indicates the amount of the active ingredient, the high amount of active oxygen indicates that the solubility of the curing agent in the resin and the compatibility between the curing agent fragments and the molded article are excellent, and the It is preferable in various physical properties. However, in general, the higher the amount of active oxygen, the higher the risk. Also, the faster the curing, the faster the curing speed (the faster the curing speed), the worse the storage stability becomes,
It is extremely difficult to develop a curing agent that satisfies these conflicting conditions.

For example, JP-A-1-233269 describes a peroxide composition comprising t-butylperoxybenzoate and t-butylperoxyisopropyl carbonate, but still has sufficient curing characteristics, safety, and stability. Not satisfactory, and JRKolczynski and GAHarpel reported at the 28th SPI Annual Meeting 1-D (1973) that a hardener composition consisting of t-butylperoxyisopropyl carbonate and t-butylperoxyoctoate was used. It has been reported, however, to have a significant lack of stability upon storage.

<Problems to be Solved by the Invention> Therefore, practically, it satisfies the curing performance and the quality of the molded article equal to or more than t-butyl peroxyisopropyl carbonate, and the safety equal to or more than t-butyl peroxybenzoate, There is a strong need for a stable curing agent composition.

<Means for Solving the Problems> The inventors of the present invention have conducted intensive studies in order to respond to the above demand, and as a result, a peroxide composition having a specific ratio of t-butylperoxyisopropyl carbonate and peroxyketal has excellent properties. And found that the present invention was achieved. That is, the present invention relates to 45 to 85% by weight of t-butyl peroxyisopropyl carbonate and 55 to 15% by weight. (Wherein, when R is a hydrogen atom, R ′ is an ethyl and propyl group, and when R is a methyl group, R ′ is methyl,
Ethyl and propyl groups), characterized in that it does not contain a diluent,
A peroxide composition having an active oxygen content of 8.6% or more. Despite having a high active oxygen content, it has excellent stability and safety during storage and has excellent performance as a curing agent for molding materials such as SMC and BMC.

The t-butyl peroxyisopropyl carbonate used in the present invention can be produced by a known method by reacting isopropyl chloroformate with t-butyl hydroperoxide in the presence of an alkali. The peroxyketal includes 1,1-bis (t-amylperoxy) cyclohexane; 1,1-bis (t-hexylperoxy) cyclohexane; 1,1-bis (t-butylperoxy)- 3,3,5-trimethylcyclohexane; 1,1-
Bis (t-amylperoxy) -3,3,5-trimethylcyclohexane; 1,1-bis (t-hexylperoxy)-
Examples thereof include 3,3,5-trimethylcyclohexane and the like, which can be produced by a known method by reacting a corresponding cyclic ketone with a t-alkyl hydroperoxide in the presence of an acidic catalyst.

Table 1 shows the amount of active oxygen of various peroxides contained in the peroxide of the present invention and peroxides conventionally used as a curing agent (all are high-purity industrial products).
It shows the half-life value at 100 ° C, which indicates the explosive power and thermal decomposition characteristics, indicated by the ballistic mortar value (relative value to trinitrotoluene), and the self-accelerated decomposition temperature, which indicates the stability during storage.

Next, a method of measuring the above characteristics will be described.

Half-life: The decomposition in a 0.1 mol / benzene solution was tracked by a change in the amount of active oxygen, and the time was determined as the time when the initial value of the amount of active oxygen became 1/2.

Active oxygen content: represents the concentration of peroxide group in the sample,
It was determined by an iodine titration method using a ferric chloride solution.

Decomposition and explosive power: The explosive power of the sample when the power of trinitrotoluene is set to 100 when 10 g of the sample is charged into a ballistic mortar tester and decomposed by a No. 6 primer. It is possible to know the relative explosive power when a large amount of peroxide is decomposed, and the higher the value, the higher the risk.

Self-accelerated decomposition temperature: determined according to the BAM method,
A 400 ml sample was placed in a 500 ml dewar in a thermostat, and when the set temperature was changed in steps of 5 ° C., the lowest thermostat temperature at which self-accelerated decomposition occurred within 7 days was determined. 30 ℃ lower than this temperature is the storage temperature, 10 ℃
A lower temperature is a measure of the handling temperature.

Table 1 shows that the decomposition and explosion power of t-butyl peroxyisopropyl carbonate is very high compared to the amount of active oxygen, and for peroxyketal, the value of the amount of active oxygen increases and the power of decomposition and explosion increases. It is shown that. Regarding the thermal decomposition properties, in the half-life, both t-butyl peroxyisopropyl carbonate and peroxyketal are more easily decomposed than t-butyl peroxybenzoate, and t-butyl peroxyisopropyl carbonate and peroxyketal The comparison shows that the latter is about three times faster than the former. But
Conversely, the self-accelerated decomposition temperature is higher for peroxyketal, indicating that decomposition is difficult. This indicates that the thermal decomposition behavior (mechanism) of t-butyl peroxyisopropyl carbonate is significantly different from that of peroxyketal. The composition of the present invention is composed of t-butyl peroxyisopropyl carbonate and peroxyketal, and the mixing can be easily carried out simply by mixing both of them, and the mixing ratio is t-butyl.
45 or more butyl peroxyisopropyl carbonate
85% by weight, 55 to 15% by weight of peroxyketal and an active oxygen content of 8.6% or more.
0 to 80% by weight, the latter 50 to 20% by weight. If the amount of peroxyketal exceeds 55% by weight, there is a problem in the curing performance such as surface appearance characteristics of the molded article, which is less than 15% by weight. I can't get it. When the amount of active oxygen is less than 8.6%, a problem occurs due to a decrease in the amount of the active ingredient of the curing agent.

The unsaturated polyester resin referred to in the present invention is a vinyl monomer obtained by heating and dehydrating and condensing a glycol with an unsaturated dibasic acid in combination with a saturated dibasic acid if necessary. The vinyl S resin is obtained by diluting with polyepoxide and α, β
It is obtained by diluting an equivalent amount of an unsaturated-basic acid with a vinyl monomer. In the present invention, the present invention can be applied to a resin generally called a radical-curable thermosetting resin.

In the present invention, the rate of pyrolysis is not greatly reduced, but the pyrolysis mechanism is significantly different. It consists of mixing two peroxides in a specific ratio. For this reason, the radial active species generated by the decomposition of one peroxide interacts with the radical active species generated by the decomposition of the other peroxide, thereby exhibiting excellent characteristics that cannot be expected from the properties of both. Seems to be something.

<Effects of the Invention> Since the present invention is constituted as described above, the peroxide composition has (1) remarkably improved stability during storage, and (2) remarkable power when decomposed and exploded. When used for molding materials such as SMC, BMC, etc., (3) the curing time can be shortened while maintaining the flow characteristics of the molding material, and it is useful for shortening the molding cycle. 4) The pot life and shelf life of the molding material can be lengthened, and (5) a molded article having excellent surface appearance characteristics can be obtained.

<Examples> Hereinafter, the present invention will be described with reference to Examples, Comparative Examples, and Reference Examples, all of which are for illustrative purposes and do not limit the present invention.

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

Next, each composition was used as a curing agent, and was used in an amount of 1% by weight with respect to an unsaturated polyester resin for housing SMC (Polymer B manufactured by Takeda Pharmaceutical Co., Ltd.), according to a method according to JIA K-6901. A heat curing test and a pot life measurement experiment were performed to measure the gel time, the curing time, and the pot life.

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

That is, 70 parts of an unsaturated polyester resin (Polylite PS-260 manufactured by Dainippon Ink and Chemicals, Inc.), 30 parts of a low shrinkage agent (MODIPA SV10B-30 manufactured by NOF Corporation), 6 parts of zinc stearate, calcium carbonate One part of the peroxide composition of the present invention was added to 130 parts and 1 part of magnesium oxide, and the mixture was mixed by a mixer so as to be sufficiently uniform to adjust a dope. This dope was poured into a polyester film on which a strand mat was set, and the mat was impregnated to form a sheet. This is placed in a 40 ° C constant temperature room for 48 hours.
The viscosity was increased over time to obtain an SMC molding material. The molded product was molded at a molding temperature of 145 ° C. for 6 minutes to obtain a molded product of 120 × 120 × 3 mm. The surface condition was visually observed to determine the appearance characteristics.

Table 2 shows the composition of the peroxide composition and the measurement results.

In the figure, ◎: very good surface gloss; ：: good surface gloss; Δ: blooming occurred on the surface, resulting in poor gloss.

Comparative Examples 1 to 9 Next, the ratio of t-butyl peroxyisopropyl carbonate to peroxyketal was determined in the same manner for the composition outside the present invention, the typical conventional composition, and the curing agent, in the same manner as in the amount of active oxygen and decomposition explosion. The power, self-accelerated decomposition temperature, curing characteristics, pot life, and surface appearance characteristics of molded products were examined. Table 2 shows the results. In addition, in the characteristics of t-butyl peroxyisopropyl carbonate and t-butyl peroxybenzoate, () indicates the values shown in Table 1.

As is clear from Table 2, the composition of the present invention has a longer pot life than the conventional compositions t-butyl peroxyisopropyl carbonate and t-butyl peroxyoctoate (Comparative Example 4), Compared with -butylperoxyisopropyl carbonate and t-butylperoxybenzoate, the pot life is longer and the curing speed is faster (Comparative Example 5).
Compared with 1,1-bis (t-hexylperoxy) cyclohexane, the curing speed is faster (Comparative Example 6) and the surface properties are better (Comparative Example 6), and 1,1-bis (t-butylperoxy) cyclohexane. ) It can be seen that the pot life is longer than that of 3,3,5-trimethylcyclohexane and t-butyl peroxyoctoate (Comparative Example 7) and the surface properties are good (Comparative Example 7). In addition, in the composition of the present invention, when the amount of 1,1, -bis (t-hexylperoxy) cyclohexane exceeds 50%, the surface properties of the molded product are significantly reduced (Comparative Example 1),
Furthermore, compared to high-purity t-butylperoxyisopropyl carbonate, it has a longer pot life and is faster curing (Comparative Example 8), and has a significantly higher curing speed than Comparative Products diluted with 75% solvent (Comparative Example 3); Good surface characteristics (Comparative Example 3).

As shown in the above Examples and Comparative Examples, the composition of the present invention has significantly improved safety and stability as compared with t-butylperoxyisopropyl carbonate, and
It can be seen that it is equal to or more than butyl peroxybenzoate and has excellent curing properties.

────────────────────────────────────────────────── ─── Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) C08F 4/32-4/38 C08F 290/06 C08F 299/02-299/04 CAS ONLINE

Claims (1)

(57) [Claims] (1) 45 to 85% by weight of t-butyl peroxyisopropyl carbonate and 55 to 15% by weight of (Wherein, when R is a hydrogen atom, R ′ is an ethyl and propyl group, and when R is a methyl group, R ′ is methyl,
And a peroxyketal represented by the formula (1), wherein the active oxygen content is 8.6% or more, and which is excellent in safety and stability.