JPS58145738A - Production of unsaturated polyester resin foam - Google Patents

Abstract

PURPOSE:To obtain the titled foam article, by adding two specified kinds of components to a mixture consisting of an unsaturated polyester resin compsn., dinitrosopentamethylene tetramine and an org. peroxide, and efficiently expanding the mixture. CONSTITUTION:Dinitrosopentamethylenetetramine as a thermal decomposition type blowing agent and an org. peroxide are mixed with an unsaturated polyester resin compsn. Further, 0.001-1pt.wt. (per 100pts.wt. unsaturated polyester resin) org. compd. (A) having at least one group selected from those of formula I(wherein R1 is H, NH2, a group of formula II wherein R2-R4 are each H, alkyl) and 0.2-10pts.wt. (per 100pts.wt. said polyester resin) org. compd. (B) having at least one group selected from those of formula III (wherein R5 is H, alkyl; A is O, S, NH) are added thereto. The mixture is expanded to obtain the titled foam.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing unsaturated polyester resin foams. More specifically, when an unsaturated polyester resin composition is mixed with a pyrolyzable blowing agent dinitrosopentamethylenetetramine (hereinafter abbreviated as DPT) and an organic peroxide and heated to foam and harden to form a foam, the ingredients are A and component B
It relates to a method for producing an unsaturated polyester resin foam, which comprises adding two components.

Unsaturated polyester resins have excellent mechanical strength, heat resistance, etc., so their uses are expanding to various fields. However, since it usually contains multi-star fillers and fiber reinforcing materials, its specific gravity is large, and there are considerable limitations on the expansion of its uses. Weight reduction has been achieved by adding hollow bodies such as glass balloons, but there is a limit to this, and the best that can be done is to reduce the weight by about 20%.

Therefore, weight reduction by foaming unsaturated polyester resin,
Furthermore, N4's insulation properties are extremely significant. Various attempts have been made to do so, but the current situation is that the area is very rural and has not yet been industrialized.

In order to properly foam unsaturated polyester resin, the timing of gas generation from the foaming agent and gelation of the resin must match. However, even if the substances normally used as blowing agents generate gas when decomposed,
Even if the gas is generated by evaporation or by some other mechanism, it is extremely difficult to time the gas generation to the period when the resin viscosity is suitable for foaming. This is due to the following properties of unsaturated polyester resin. That is, the curing reaction of unsaturated polyester resin is radical copolymerization, and the speed is very fast and the viscosity increases rapidly, so the period when the resin viscosity is suitable for foaming is short. Therefore, the generation of gas from the resin 1 occurs when the viscoelasticity of the resin is low, or occurs near or after curing. Therefore, the generated gas becomes large bubbles and escapes from the resin system,
Even if a foam is obtained, it will be cracked and shattered.

Methods for foaming unsaturated polyester resin using various pyrolytic foaming agents are already known, but in either case, as mentioned in AiJ, the timing of gelation of the resin and generation of gas from the foaming agent is dependent on the timing. Because they do not match, gas leakage occurs, cracks form, and unsatisfactory foams are not acceptable.

The present inventor has completed the present invention as a result of intensive research into 4aT in order to provide a new and improved manufacturing method for unsaturated polyester/I/resin foam.

The present invention is a modification of the centering method for unsaturated polyester (V) resin using the pyrolytic foaming agent DPT, and the key point is to foam by controlling the gelation rate of the unsaturated polyester camellia resin. The period when the resin viscosity is suitable for foaming is extended, and the gas generation due to the decomposition of DPT is controlled so as to be timed to the period when the resin viscosity is suitable for foaming.

1) When foaming with PT alone, relatively high gas generation is observed, but gas generation is also observed before and after the period when the resin viscosity is suitable for foaming, and the foam surface becomes rough due to gas release. In addition to this, it also causes cracks in the foam.
Furthermore, since the heat of decomposition of DPT is very large, there is a drawback that the core is burnt. Even if a decomposition aid is used in combination with DPT, the above-mentioned drawbacks cannot be solved by merely lowering the decomposition temperature.

By slightly adding addition test 11, the present inventor
Efficient foaming can be achieved by effectively utilizing the gas generated from the foaming agent, and the surface is smooth and free from coarse bubbles or cracks that degrade the important mechanical properties of the foam when using only D I) T. Furthermore, we have discovered that it is possible to create products that do not burn due to partial heat storage. The present invention provides a method for easily producing a centering body by thermoforming desired unsaturated polyester resin, for example, by ordinary heat molding, BMC, SMC, etc., and makes a significant contribution to industry. It is.

The resin viscosity in the present invention refers to the viscoelasticity of the resin, regardless of the addition of fillers or other compounding agents, and the resin viscosity suitable for foaming refers to the resin viscosity that allows residual gas to form bubbles from the foaming stage 11. It means a state in which it has viscoelasticity that can be maintained until it collapses and can expand in volume as gas is generated. Further, the term "period of resin viscosity suitable for foaming" means a period of time during which the resin viscosity is within the range of viscosity suitable for foaming while gelation of the resin progresses. Figure 1.2.3.4 shows the viscosity (η
) shows the relationship between the change in gas generation amount (V) of the blowing agent, and curve 1.3.5.7 is the viscosity change curve, curve 2.
4.6.8 is the decomposition gas generation curve of the blowing agent.

In FIG. 1, the viscosity in range l is too low to hold gas. Range ■ (shaded area) is the resin viscosity suitable for foaming. In the range ■, the resin has almost no viscoelasticity and is close to being cured, and the generation of gas in this range causes cracks.

Figure 1 shows a state in which gas generation from the foaming agent occurs within a range of resin viscosity suitable for foaming (period t1 to t2), and the timing of foaming and gelation is synchronized; in this case, A good foam is obtained. Figure 2.3.4 shows a state in which gas generation from the foaming agent occurs even in a resin viscosity range that does not allow foaming, and the timing of foaming and gelation is out of sync. In Figure 2.4, the period of resin viscosity suitable for foaming is short, and in Figure 3.4, the decomposition range of the foaming agent is too wide, so the timing of foaming and gelation does not match. In the case of Figure 2.4, surface roughness and cracks occur, and in the case of Figure 3, cracks occur.

1. By using component A and component B together in DPT, the present invention creates the relationship between the viscosity change of unsaturated polyester (V) resin and gas generation from the blowing agent, that is, gelation and foaming, as shown in FIG. 1. By controlling the
This makes it possible to produce a good foam.

Component A includes some that are normally used as blowing agents, but the amount used in the present invention is small and is effective for foaming.
It does not have a role as a WIJ, but is used in a catalytic sense. The effect appears only when DPT and component B are used in combination. Although it is extremely difficult to elucidate it theoretically, Components A and B have the effect of changing the gelation rate of unsaturated polyester resin and maintaining the resin viscosity suitable for foaming for a long time, and the decomposition of DPT that makes it suitable for foaming. They discovered that it has the effect of sharply controlling the resin viscosity. Component A and component B are thought to have a synergistic effect, which affects both the resin and DPT and maintains a good balance between them. That is, it is considered that there is some kind of relationship between the effects of component A and component B on the resin and on DPT, and that they influence each other.

The unsaturated polyester resin referred to in the present invention is a resin obtained by dissolving an unsaturated polyester base obtained from an unsaturated polybasic acid, a saturated polybasic acid, and a polyhydric alcohol as raw materials in a polymerizable vinyl hexamer. Unsaturated polyester bases are usually obtained by the condensation reaction of an unsaturated di-salt with an acid and a di- or tri-hydric alcohol compound such as a glycol, and in order to control the reactivity of the unsaturated resin, a saturated di-basic acid paste is added. Saturated polybasic acids or their anhydrides are often used in conjunction with unsaturated acids or their anhydrides.

Examples of the unsaturated dibasic acid used as a raw material for the unsaturated polyester base include maleic acid, fumaric acid, citraconic acid, chloromaleic acid, allylsuccinic acid, itaconic acid, mesaconic acid, and anhydrides thereof. or,
Examples of the saturated dibasic acid include phthalic acid, isophthalic acid, themphthalic acid, adipic acid, succinic acid, and sepatic acid. In addition, as glycols, ethylene glycol, diethylene glycol, propylene glycol,
Examples include ethylene oxide, fluoropylene oxide, hydrogenated hisphenol A, bisphenol A, and the like.

Examples of the polymerizable vinyl septamer added to the unsaturated polyester resin include nutyrene, vinyltoluene, α-methylstyrene, chlorostyrene, and vinylbenzene.
Examples include 11-allyl cyanurate, methyl methacrylate, methyl acrylate-1-, and mixtures thereof.

Organic peroxides used in the present invention include benzoyl peroxide, cyclohegisanone peroxide, t-butyl hydroperoxide, lauroyl peroxide, methyl ethyl ketone peroxide, t-
Examples include butylperoxybenzoate, t-butylperbenzoate-1-, cumene hydroperoxyside, dicumyl peroxybenzoate, and the like. The amount used is 71 parts by weight per 100 parts by weight of unsaturated polyester/1/resin, and a range of 01 to 5 parts by weight is suitable for energization. If the amount of organic peroxide used is too small, curing of the unsaturated polyester resin will not be completed, and if it is too large, curing will proceed too rapidly and a foam with uniform fine cells will not be obtained.

The amount of DPT used in the present invention varies depending on the specific gravity of the target foam molded product, the amount of filler to be blended, the amount of fiber reinforcing material, etc. The range is appropriate. If the amount of DPT used is too small, a foam with a sufficient expansion ratio cannot be obtained, and if it is too large, a foam with uniform fine cells cannot be obtained, and furthermore, the mechanical strength is lowered.

Component A used in the present invention is selected from the group consisting of groups having 1 formula R, -N-8- in the molecule.
1 O An organic compound containing at least one group,
Specifically, nurphanilamide, benzenesulfamide, benzenesulfonylhydrazide, benzenesulfonylsemicarbazide, pencenesulfonylacetohydrazone, p-toluenesulfonylhydrazide, p-toluenesulfonylsemicarbazide, 4.4/-oxybis (benzenesulfonyl hydrazide), 4,4'-oxybis(benzenesulfonyl semihydrazide), 4,4'-
Oxybis (pensene sulfonylacetohydrazone compound) can also be used in combination of two or more kinds.The amount used is as follows:
0001 per 100 parts by weight of unsaturated polyester resin
A suitable amount ranges from 0.001 to 0.05 parts by weight. If the amount of component A used is too small, no effect will be exhibited, and if it is too large, cracks will occur in the foam.

Component B used in this study has the formula R5-N in the molecule.
An organic compound containing at least one group selected from the group consisting of groups having -C-,
Specific examples include formamide, acetamide, benzamide, oxamide, oxamic acid, urea, nitrourea, formilunurea, thiourea, ethylthiourea, biuret, dicyandiamide, semi-irbazi F, and the like. Furthermore, two or more of the above compounds can also be used in combination. The amount used is
The appropriate amount is in the range of 0.2 to 10 parts by weight based on the unsaturated polyester lILJIIfi ] o □ parts by weight. If the amount of component B used is too small, the foam will crack and burn, while if it is too large, the surface of the foam will lack smoothness and the critical ratio will decrease.

In the present invention, the addition of fillers, fiber reinforcing materials, thickeners, colorants, mold release agents, foam stabilizers, flame retardants, etc. is not prohibited, and may be used as necessary.

The unsaturated polyester resin foam obtained by the present invention has excellent mechanical strength, heat resistance, heat insulation, chemical resistance, light stability, and dimensional stability, and its uses include automobiles,
Can be used in a wide range of fields such as electrical equipment and building materials.

The present invention will be described in detail below with reference to Examples.

Examples 1 to 9 To 100 parts by weight of unsaturated polyester resin, 1 part of 1-butyl peroxybenzoate IN, 1 part of calcium lj2 acid
00 parts by weight, 4 parts by weight of zinc stearate, 15 parts by weight of magnesium oxide, DPT and component A in the amounts shown in Table 1 below.
1 component B was sufficiently stirred and mixed. After impregnating 85 parts by weight of glass fiber with the obtained mixture, the mixture was thickened at 40°C for 2 days.

This foamable resin composition was placed in a square mold with a depth of 5 mm and 150 questions, and heated at 145° C. under a pressure of 100 Kp/rrA for 1 minute and under a contact pressure for 3 minutes to foam and harden it. The results are shown in Table 1, and all the cells were uniform and fine foams with smooth surfaces.

Comparative Example 1 A resin composition was prepared in which DPT, component A, and Bf were omitted in the example, and the mixture was heated to 1o o K at 145°C.
It was cured by heating for 4 minutes under a pressure of y/d.

This is normal FRP heat forming. The results are listed in Table 2.

Comparative Examples 2 to 6 In the examples, DPT, component A and component B were mixed as shown in Table 2 below, and the same operations as in the examples were carried out. In neither case was a satisfactory foam obtained. The results are listed in Table 2.

Table 1 Table 2 * The amount of compounding agents added depends on the unsaturated point. rieste) V resin 100 parts by weight parts by weight.

** Foam evaluation: ○: Good ×: Bad

[Brief explanation of the drawing]

1 to 4 are viscosity change curves of unsaturated polyester resins and decomposition curves of blowing agents under heating. The horizontal axis is time t1
The vertical axis represents the resin viscosity η and the amount of gas generated V. Patent applicant Hydraulic Chemical Industry Co., Ltd. Figure 3 65 t-chi

Claims (1)

[Claims] When dinitro, soventamethylenetetramine, and an organic peroxide are mixed into an unsaturated IJ ester resin composition, and the mixture is heated and foamed to harden to form a foam, the following two components are added. A method for producing an unsaturated polyester resin foam, characterized by: (2) Component A 1 An organic compound containing at least one group selected from the group consisting of a group having the formula R, -N-8- in the molecule. In the formula, R1 is H, NH, (R2, R3, R4 are the same or different and represent H1 alkyl occupancy (). 2) Component B A group having the formula R5-N-C- in the molecule. An organic compound containing at least one group selected from the group consisting of: In the formula, R5 is H1 alkyl group, A is 0,81NH
shows.