JP2012224775A - Radically curable resin composition for molding, and resin-molded article - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a radically curable resin composition for molding, which can be rapidly cured without foam formation.SOLUTION: The radically curable resin composition for molding contains a radically reactive monomer, a radically curable thermosetting resin, and a radical curing agent. The radically curable resin composition contains, as the radical curing agent, at least: a curing agent A that is decomposed in a temperature range in which the radically reactive monomer is evaporated and foamed, namely, in a temperature range of ±20°C around its boiling point; and a curing agent B that is decomposed at temperature lower by 20°C or more than the decomposition temperature of the curing agent B. The total amount of curing agents A and B thus contained is 0.5 to 5.0 pts.mass based on 100 pts.mass of the total amount of the radically reactive monomer and the radically curable thermosetting resin.

Description

  The present invention relates to a radical curable molding resin composition and a resin molded product that can be rapidly cured without foaming.

  In general, it is known to increase the amount of a curing agent in order to quickly cure a radical curable resin. However, the curing rate can be increased by simply increasing the amount of the curing agent, but because of the rapid generation of heat, gelation occurs partially, and the surface of the molded product is roughened or blown off by the so-called pregel phenomenon. In some cases, surface defects, such as

  As an improvement, two curing agents with slightly different decomposition temperatures are used in combination, and the curing of the resin is started early in the heating process during molding, resulting in a rapid curing and molding technique. Various resin compositions have been tried.

During the heating process in the press molding method, etc., the curing agent of the medium / low temperature decomposition type organic peroxide is first decomposed at around 70 ° C. to start the curing reaction, and then the temperature rises due to its induction effect and external heating. Thus, at around 100 ° C., the high-temperature decomposable organic peroxide curing agent is decomposed and the resin is further cured by the radicals.
(See Patent Documents 1 to 3)

JP-A-55-145719 Japanese Patent Laid-Open No. 10-15896 JP 2000-238058 A

  However, in the radical curing type molding resin composition used in combination with the curing agent described above, even if the rough surface of the pregel phenomenon and the flow pattern due to the fluid pregel phenomenon can be suppressed, the appearance defect of fine surface defects, the molding cycle shortening, etc. This solution remains a problem.

That is, the radical reactive monomer blended and used in the radical curable resin gradually evaporates and foams at the time of heat molding, and the bubbles cause poor appearance.
The radical reactive monomer is an indispensable component blended in the radical curable resin for the convenience of the radical curable resin and the convenience of molding work. It will be necessary.

  Therefore, in the present invention, a radical curable molding resin capable of suppressing evaporation / foaming of the radical reactive monomer during molding of the radical curable resin containing the radical reactive monomer and improving the appearance of the molded product. It is an object to provide a composition and a resin molded product.

In order to solve the above-mentioned problems, a radical curable molding resin composition of the present invention comprises a radical reactive monomer, a radical curable thermosetting resin, and a radical curable molding resin containing a radical curing agent. A composition, wherein the radical curing agent is at least a curing agent A that decomposes in a temperature range within a temperature difference of ± 20 ° C. around a boiling point that is a temperature range in which the radical reactive monomer evaporates and foams;
A curing agent B that decomposes at a temperature 20 ° C. or more lower than the decomposition temperature of the curing agent A,
The total blending amount of both curing agent A and curing agent B is the total amount of radical reactive monomer and radical curable thermosetting resin: 0.5 parts by mass or more and 5.0 parts by mass with respect to 100 parts by mass. It is characterized by being less than part.

In the radical curable molding resin composition of the present invention, the mass ratio B / A between the curing agent A and the curing agent B is preferably in the range of 0.5 to 5.
In the radically curable molding resin composition of the present invention, the radically curable thermosetting resin is one or more resins selected from unsaturated polyester resins, allyl resins, and vinyl ester resins. The radical reactive monomer is preferably one or more monomers selected from styrene, α-methylstyrene, fumaric acid, and methyl methacrylate.

  Furthermore, the resin molded product of the present invention is characterized in that one of the above-mentioned radical curable molding resin compositions is heat-cured and molded.

  The radical curable molding resin composition of the present invention can suppress evaporation and foaming of radical reactive monomers during molding of radical curable resins containing radical reactive monomers, thereby improving the appearance of molded products. The molding cycle can be shortened.

Embodiments of the present invention will be described below.
The present invention provides a radical curable molding resin composition that can be rapidly cured with little foaming.
The radical curable molding resin composition of the present invention is a radical curable molding resin composition containing a radical reactive monomer, a radical curable thermosetting resin, and a radical curing agent, the radical curing agent. At least in the temperature range where the radical-reactive monomer evaporates and foams, that is, the curing agent A that decomposes in the temperature range within a temperature difference of ± 20 ° C. around the boiling point, and 20 ° C. higher than the decomposition temperature of the curing agent A And a curing agent B that decomposes at a low temperature.

[Radically reactive monomer]
Examples of the radical reactive monomer in the present invention include styrene, α-methylstyrene, fumaric acid, methyl methacrylate and the like.

[Radical curable thermosetting resin]
The radical curable thermosetting resin in the present invention may be a radical curable resin such as unsaturated polyester resin, allyl resin, vinyl ester resin, etc., and there are no restrictions on the average molecular weight and molecular structure. Can be selected according to physical properties. Moreover, the radical reactive monofunctional monomer and polyfunctional monomer may be included as a diluent.

[Radical curing agent]
Examples of the radical curing agent in the present invention include methyl ethyl ketone peroxide, benzoyl peroxide, lauroyl peroxide, stearoyl peroxide, bis (4-t-butylcyclohexyl) peroxydicarbonate, and t-hexylperoxy-2-ethylhexa. Examples thereof include organic oxides such as noate, t-butylperoxy-2-methylcyclohexane, t-aluminum peroxybenzoate, and dicumyl peroxide.

The decomposition temperature of the radical curing agent in the present invention is a temperature at which the half-life is 10 hours, that is, a 10-hour half-life temperature (T10).
The radical curable molding resin composition of the present invention comprises a curing agent A that decomposes in a temperature range within a temperature difference of ± 20 ° C. with a boiling point being a temperature range in which radical reactive monomers are evaporated and foamed, and this curing agent. And a curing agent B that decomposes at a temperature 20 ° C. or more lower than the decomposition temperature of A.

  When two types of curing agents that approximate a decomposition temperature difference of 20 ° C or less cannot be used together, evaporation and foaming of the radical-reactive monomer cannot be sufficiently suppressed, and curing proceeds rapidly due to the action of both curing agents during the heating process. As a result, the amount of heat generated increases, and evaporation and foaming of radical reactive monomers are activated, which must be avoided.

  The total blending amount of both curing agent A and curing agent B is the total amount of radical reactive monomer and radical curable thermosetting resin: 0.5 parts by mass or more and 5.0 parts by mass with respect to 100 parts by mass. Less than part. If it is less than 0.5 parts by mass, the curing reaction takes a long time even if it is heated sufficiently, which is inconvenient, and if it is 5.0 parts by mass or more, the curing reaction rapidly proceeds and the foaming of the radical reactive monomer is suppressed. This is because there is a concern that the surface of the molded product may be roughened.

The mass ratio B / A between the curing agent A and the curing agent B is in the range of 0.5-5.
When the amount of the curing agent B is small and B / A is less than 0.5, the curing reaction in the low and medium temperature range is too slow, and in the situation where the curing agent B is large and the curing agent A is small and B / A exceeds 5. This is because the curing reaction in the high temperature range is too slow and the evaporation and foaming of the radical reactive monomer cannot be sufficiently suppressed.
If the above noted points are observed, three or more kinds of curing agents can be used in combination as necessary.

[Inorganic filler]
The radical curable molding resin composition of the present invention may contain various known inorganic fillers. Examples of the inorganic filler include inorganic fillers such as aluminum hydroxide, calcium carbonate, barium sulfate, silica, alumina, glass fiber, silica sand, and talc. If necessary, they can be used alone or in combination of two or more.

[Other ingredients]
The radical curable molding resin composition of the present invention may further contain other components within a range not impairing the effects of the present invention. Specific examples of such other components include flame retardants, adhesion promoters, colorants, antifoaming agents, coupling agents, and the like.

[Applicable molding method]
The radical curable molding resin composition of the present invention can be applied to various molding methods such as compression molding, transfer molding, BMC method, SMC method and the like.

[Applicable uses]
The radical curable molding resin composition of the present invention can be applied to uses such as bathtubs, cooling towers, water tanks, septic tanks, automobile parts, and electrical equipment parts by the various molding methods described above.

Next, the present invention will be specifically described with reference to examples.
Example 1
100 parts by mass of unsaturated polyester resin “Rigolac 158BQT (Showa High Polymer)” containing 20-30% styrene monomer (boiling point 145 ° C.) and 100 parts by mass of calcium carbonate “SS # 30 (Nitto Flour Industry)” Thus, a thermosetting unsaturated polyester resin composition was obtained.

  Next, as a curing agent, 0.5 mass of a di-t-butyl peroxide “Kayabutyl D (Kayaku Akzo)” whose decomposition temperature (meaning “10-hour half-life temperature”, hereinafter the same) is 126 ° C. Part and a resin composition obtained by combining 1.0 part by mass of t-amylperoxy 2-ethylhexanate “Trigonox 121-50E (Kayaku Akzo)” having a decomposition temperature of 70 ° C. Was cast into a test mold having a mold temperature of 7 mm, an upper mold temperature of 130 ° C., and a lower mold temperature of 150 ° C., and heated for 1 hour to obtain a molded product.

(Example 2)
As for the curing agent, 1.0 part by mass of di-t-butyl peroxide “Kayabutyl D (Kayaku Akzo)” having a decomposition temperature of 126 ° C. and cumene hydroperoxide “Kayakumene H” having a decomposition temperature of 159 ° C. A molded product was obtained in the same manner as in Example 1 except that the amount was 0.5 parts by mass.

(Example 3)
0.5 parts by mass of di-t-butyl peroxide “Kayabutyl D (Kayaku Akzo)” having a decomposition temperature of 126 ° C. and t-butyl peroxyisopropyl carbonate “Kayacarbon” having a decomposition temperature of 97 ° C. A molded product was obtained in the same manner as in Example 1, except that 1.0 part by mass of “BIC-75 (Kayaku Akzo)” was used.

Example 4
The curing agent was divided into 0.5 parts by mass of di-t-butyl peroxide “Kayaptil D (Kayaku Akzo)” having a decomposition temperature of 126 ° C., and t-butyl peroxyisopropyl carbonate “Kaya-Carbon BIC-75” having a temperature of 97 ° C. (Chemicals Akzo) ”0.4 parts by mass and t-amylperoxy 2-ethylhexanate“ Trigonox 121-50E (Chemicals Akzo) ”with a decomposition temperature of 70 ° C. Obtained a molded product in the same manner as in Example 1.

(Comparative Example 1)
A molded product was obtained in the same manner as in Example 1 except that the curing agent was changed to only 1.5 parts by mass of di-t-butyl peroxide “Kayabutyl D (Kayaku Akzo)” having a decomposition temperature of 126 ° C.
(Comparative Example 2)
A molded product was obtained in the same manner as in Example 1 except that only 1.5 parts by mass of dicumyl peroxide “Kayakmir D (Kayaku Akzo)” having a decomposition temperature of 117 ° C. was used as the curing agent.

(Comparative Example 3)
A molded product was obtained in the same manner as in Example 1 except that the curing agent was only 1.5 parts by mass of t-butylperoxyisopropyl carbonate “Kaya-Carbon BIC-75 (Kayaku Akzo)” having a decomposition temperature of 97 ° C. It was.
(Comparative Example 4)
As a curing agent, 0.5 parts by mass of di-t-butyl peroxide “Kayabutyl D (Kayaku Akuzo)” having a decomposition temperature of 126 ° C. and dicumyl peroxide “Kayakmir D” having a decomposition temperature of 117 ° C. A drug product was obtained in the same manner as in Example 1 except that the amount was 1.0 part by mass.

[Formulation composition and evaluation results of each example and comparative example]
Table 1 summarizes the composition and evaluation results of the examples and comparative examples.
“Resin exothermic peak time” in the experimental result column indicates the time (minutes) from the start of heating of the resin composition to the exothermic peak of the resin composition.

When the radical curable resin composition for molding is heated and molded, if the time to reach the exothermic peak is short, the time to reach the desired cured state is shortened, so the curing speed is increased.
As a determination of the curing rate, a value of time to reach this exothermic peak was 15 minutes or less, and “O” was marked as “rapid curing”. Those marked with less than half of the estimated time (Example 4) and (7 minutes) were marked with ◎. On the other hand, Δ marks were given to those exceeding 15 minutes and 20 minutes or less, and X marks were attached to those exceeding 20 minutes.

  In radical curing type thermoforming, in order to avoid temporary stress due to curing shrinkage caused by the curing reaction, deformation and warping, resulting in molding defects, heating in the mold is continued for a while. It is usual to do.

  “Appearance of molded product” in the evaluation result column is a result of detailed visual observation on the surface of the molded product whether there are fine irregularities due to monomer foaming, rough skin due to pregel phenomenon, and flow pattern due to fluid pregel phenomenon. Indicates. The ○ marks are those without any appearance defects, and comments on the extent and content of those with appearance defects.

  From Table 1, in each example, the surface of the molded product has an excellent appearance without fine irregularities due to the foaming of the monomer, rough skin due to the pregel phenomenon, and a flow pattern due to the fluid pregel phenomenon, and heat generation. The time to reach the peak was “fast curing” in 15 minutes or less.

  In particular, Example 4 is a combination of three types of curing agent A (decomposition temperature 126 ° C.) and curing agent B (decomposition temperature 70 ° C.) plus a third curing agent C (decomposition temperature 97 ° C.). The difference in decomposition temperature between each other is 20 ° C. or more, and the blending amount is also dispersed. In the heating process, the situation where the curing proceeds rapidly due to the concomitant agent is avoided, so that the evaporation / foaming of the monomer is sufficiently suppressed, In addition, the curing speed is fast. (Refer to the notes in the [Radical curing agent] column.)

On the other hand, in a comparative example, there is nothing which has favorable evaluation in both the cure rate and the external appearance.
In Comparative Example 4, 0.5 parts by mass of di-t-butyl peroxide “Kayabutyl D (Kayaku Akzo)” having a decomposition temperature of 126 ° C. and dicumyl peroxide “Kayakmir D () having a decomposition temperature of 117 ° C. The resin composition combined with 1.0 part by mass is thermoformed, but since the difference in decomposition temperature between the two curing agents is less than 20 ° C., monomer evaporation / foaming It cannot be suppressed sufficiently, resulting in poor appearance due to foaming.

Claims (4)

A radical curable molding resin composition containing a radical reactive monomer, a radical curable thermosetting resin, and a radical curing agent,
As the radical curing agent, at least a curing agent A that decomposes in a temperature range within a temperature difference of ± 20 ° C. around a boiling point that is a temperature range where the radical reactive monomer evaporates and foams,
A curing agent B that decomposes at a temperature 20 ° C. or more lower than the decomposition temperature of the curing agent A,
The total blending amount of both curing agent A and curing agent B is the total amount of radical reactive monomer and radical curable thermosetting resin: 0.5 parts by mass or more and 5.0 parts by mass with respect to 100 parts by mass. Radical curable resin composition for molding, characterized by being less than part.   2. The radical curable molding resin composition according to claim 1, wherein a mass ratio B / A between the curing agent A and the curing agent B is in a range of 0.5 to 5. 5. The radical curable thermosetting resin is one or more resins selected from unsaturated polyester resins, allyl resins, vinyl ester resins,
The radical curable molding according to claim 1 or 2, wherein the radical reactive monomer is one or more monomers selected from styrene, α-methylstyrene, fumaric acid, and methyl methacrylate. Resin composition.   A resin-molded product, wherein the radical-curable resin composition for molding according to any one of claims 1 to 3 is heat-cured and molded.