JPS604844B2 - Manufacturing method of impact-resistant molding material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an unsaturated polyester resin molding material, and particularly to a molding material having high impact resistance.

Powder, flake, or granular molding materials (hereinafter referred to as dry premix) containing at least essential components unsaturated polyester resin with a softening temperature of 60°C or higher, a crosslinking agent that is solid at room temperature, a filler, and a fiber reinforcing agent are not handled. It is in practical use as it is simple and suitable for mass production of molded products.
That is, it is easy to measure, has good storage stability and flow characteristics during molding, and is suitable for compression molding, transfer molding, or injection molding, so it is effectively used in various fields. By the way, when applying this type of molding material to injection molding,
A pellet shape with a small particle size (4 sides or less) and good weighability and hopperability is desired.

However, in order to improve the mechanical strength of molded products made from the above-mentioned dry premix, long reinforcing fibers are used as one component, but there is a limit to the blending composition ratio and due to the size of the pellet, There is a natural limit to the length, and therefore the reinforcing effect cannot be sufficiently improved. As a measure to improve the strength of this molded article, attempts have been made to appropriately select the molecular weight per double bond in the unsaturated polyester resin, but impact resistance and other properties have not been sufficiently improved.

Dry premixes containing terephthalate-based unsaturated polyester resins as the resin component are also attracting attention, as they have superior heat resistance, boiling water resistance, electrical properties, and mechanical properties compared to isophthalic acid-based unsaturated polyester resins. However, according to experiments conducted by the present inventors, the softening temperature of the resin has a significant effect on impact resistance, regardless of whether a terephthalic acid-based unsaturated polyester resin or an isophthalic acid-based unsaturated polyester resin with the same softening temperature is used. No significant difference was observed. In view of the above circumstances, the present inventors conducted extensive research and found that when a composition containing a predetermined ratio of terephthalic acid-based unsaturated polyester resin and isophthalic acid-based unsaturated polyester resin is used as the unsaturated polyester resin component, It has been found that the impact resistance is significantly improved compared to when each unsaturated polyester resin is used alone.

The present invention is based on the above findings and aims to provide a method for producing an impact-resistant molding material by which molded products with excellent impact resistance can be easily obtained.

To explain the present invention in detail below, the present invention involves mixing at least an unsaturated polyester resin, a crosslinking agent, a filler, and a reinforcing fiber, and using an extruder attached to a pelletizer equipped with an extrusion port, after heating and drying, the mixture is pelletized. In the method for producing a granular unsaturated polyester resin molding material, the above-mentioned self-unsaturated polyester resin has a softening temperature of 70 to 70, in which the self-unsaturated polyester resin contains Q.8 unsaturated dicarboxylic acid and isophthalic acid as acid components.
11000 isophthalic acid-based unsaturated polyester resin 80-95% by weight, Q.3 unsaturated dicarboxylic acid and terephthalic acid as acid components, softening temperature 70-110
Terephthalic acid-based unsaturated polyester resin 20~5℃
% by weight of an impact-resistant molding material. As described above, a dry molding material is produced by heating and kneading a mixture consisting of a solid unsaturated polyester resin, a crosslinking agent, a filler, a reinforcing fiber, and, if necessary, a template agent and a coloring agent. Softening temperature 70-110 as a solid unsaturated polyester resin
The present invention is characterized in that it uses an isophthalic acid-based unsaturated polyester resin containing a small amount of 00 terephthalic acid-based unsaturated polyester resin.

The reason why the mixing ratio of the terephthalic acid-based unsaturated polyester resin and the isophthalic acid-based unsaturated polyester resin was specifically selected as described above is as follows. That is, the content of terephthalic acid-based unsaturated polyester resin is 5% by weight.
Less than (isophthalic acid-based unsaturated polyester resin content is 9
(more than 5% by weight) and also more than 2% by weight (
Even when the isophthalic acid-based unsaturated polyester resin content is less than 8% by weight, no improvement in impact resistance is observed.
Furthermore, the ease of adding and blending reinforcing fibers is not sufficient. The isophthalic acid-based unsaturated polyester resin according to the present invention may be any unsaturated polyester resin that is solid at room temperature and has a softening temperature of 70 to 11 and 0, consisting of Q.8 unsaturated dicarboxylic acid and isophthalic acid as acid components. Although its composition and manufacturing method are not limited, preferably 30 to 70 mol% of isophthalic acid, Q.6-ethylenically unsaturated dicarboxylic acid such as maleic anhydride, fumaric acid, itaconic acid, or its anhydride are used as brewing ingredients. 30 to 70 mol% of one type or a mixture of two or more types of ethylene glycol, propylene glycol, trimethylene glycol, 1,4-cyclohexanediol, 1,3-butanediol, diethylene glycol, dipropylene as a polyhydric alcohol component. Glycol, inventyl glycol, neobentyl glycol, hydrogenated pisphenol A
An unsaturated polyester resin having an acid value of 30 or less obtained by esterifying one or more selected from the following as a reaction component at 120 to 210 o'clock in an N2 gas atmosphere is preferable. The reason why the softening temperature was limited to 70 qo to 110 oo is that if the softening temperature is 70 qo or less, it will not only greatly impair workability when pulverizing unsaturated polyester resin into powder, but also leave it at room temperature even after pulverizing it. This is because, in this case, a blocking phenomenon occurs and the storage stability is significantly reduced.

Furthermore, even if the powder is kneaded with a crosslinking agent, filler, reinforcing material, etc. immediately after pulverization and then made into a dry premix in the form of pellets, blocking of the pellets occurs and the storage stability becomes extremely low. In addition, if the softening temperature is 110°C or higher, the melt viscosity of the putty-like premix will become too high when heated and kneaded with crosslinking agents, fillers, reinforcing materials, etc., and the reinforcing fibers will break significantly in the bran. This is because the effect of addition on the impact resistance of reinforcing fibers is significantly impaired.

The terephthalic acid-based unsaturated polyester resin according to the present invention contains terephthalic acid in the main chain and has a softening temperature of 70 to 110.
Any unsaturated polyester resin may be used as long as it is a solid unsaturated polyester resin at normal temperature with a The reaction composition is one or more selected from ethylene glycol, propylene glycol, diethylene glycol, 1,4-cyclohexanediol, neobentyl glycol, water-added bisphenol A, etc. as the alcohol component. (chemical reaction) may be carried out by any method.

For example, '1' is a two-step method in which a dicarboxylic brewing component and a polyhydric alcohol component are directly reacted using an esterification catalyst, a coloring inhibitor, a polymerization inhibitor, etc., if necessary. '2
}Terephthalic acid lower alkyl ester - A transesterification catalyst is added to the polyhydric alcohol component system, and the transesterification catalyst is added to esterify it to bis-(8-hydroxyalkyl).
A method in which terephthalate is first obtained and then dehydrated with an unsaturated dicarboxylic acid; {3] a high molecular weight saturated polyester containing terephthalic acid as a brewing component is further reacted with a glycol component to obtain a depolymerized condensation product; A method of reacting saturated dicarboxylic acids. Although any method may be used, it is preferable to proceed with the reaction until the acid value reaches 30 or less. The reason why the softening temperature is limited to 70oo to 1100o is the same as that for the isophthalic acid unsaturated polyester resin. Next, examples of the present invention will be described.

[11 Production of isophthalic acid-based unsaturated polyJ ester resin Isophthalic acid 3 to 7 mol propylene glycol 1
0 to 11 mol at 120oo to 190℃ under N2 gas atmosphere
The esterification reaction was carried out to an acid value of 30 to 15, and the afterglow degree was 1.
Lower the temperature to 40oo, add 7 to 3 moles of maleic anhydride,
The acid value is 30 at 140 to 22,000 in a N2 gas atmosphere.
5 with different softening temperatures shown in Table 1.
Various isophthalic acid-based unsaturated polyester resins a to e were synthesized.

Table 1 ■ Production of terephthalic acid-based unsaturated polyester resin Transesterification reaction between dimethyl terephthalate and ethylene glycol, direct esterification reaction between terephthalic acid and ethylene glycol, or direct reaction between terephthalic acid and ethylene oxide. 1.0 to 1.1 mol of pis-(8-hydroxyethyl) terephthalate obtained by a conventionally known method such as the ethylene oxide method and 1.0 mol of maleic anhydride were mixed at 12,000 to 1.0 mol in an N2 gas atmosphere.
The esterification reaction was carried out at 210 qo to produce terephthalic acid-based unsaturated polyester resin with the softening temperature shown in Table 2.
was synthesized.

Table 2 [3' Dry premix manufacturing method The unsaturated polyester resin produced in m and
It was mixed with reinforcing fibers etc. in powder form.

Next, the obtained mixture was heated and kneaded using a press machine attached to a beletizer with a plurality of extrusion ports to produce a granular dry premix (molding material) having a particle size of 4 Yanagi or less. {4} Injection molding Using a screw type injection molding machine using a dry premix prepared by myself as a raw material, the cylinder temperature was 60 to 90.
oo, nozzle temperature 90℃, mold temperature 16000-170
qo and molding cycle 9. Specimens for impact tests were prepared under the molding conditions of silica sand.

[5' Measurement of impact strength] The notched Wizot impact strength of the molded product made from the dry premix obtained above was measured according to JIS K6911.

The composition ratio (parts by weight) of the dry premix prepared above, the impact strength (kg/skin' arc) of the molded product, and the blocking property of the dry premix (when stored at 40 qo for 9 hours) were compared with the comparative example. These are shown in Table 3.

Table 3 As is clear from Table 3, the molding materials of the comparative examples are unsuitable as dry molding materials because the blocking phenomenon occurs even when the isot impact strength is lower or higher than that of the materials according to the present invention. Not only that, but it was too soft and difficult to cut when cutting it into granules with a beletizer, and the uncut glass fibers protruded from the pellet in the form of whiskers, significantly impairing the hoverability.

In addition, isophthalic acid-based unsaturated polyester resin 'c} and terephthalic acid-based unsaturated polyester resin 'o) were used as the unsaturated polyester resins, and the composition ratios of glass fibers were changed as shown in Table 4 (
A dry premix (parts by weight) was prepared in the same manner as above.

Table 4 As is clear from Table 4, in the case of the comparative example, the Vizot impact strength is saturated when the composition ratio of glass fiber is 17 to 2 (weight ratio 17 to 20%), whereas in the case of the example In this case, the glass fiber composition ratio can be selected to be higher, and therefore the Izot impact strength also shows a higher value.

Claims (1)

[Claims] 1. A method for producing a granular unsaturated polyester resin molding material by mixing at least an unsaturated polyester resin, a crosslinking agent, a filler, and reinforcing fibers, heating and kneading the mixture using an extruder attached to a pelletizer with an extrusion port, and then pelletizing the mixture, The above-mentioned unsaturated polyester resin contains 80 to 95% by weight of an isophthalic acid-based unsaturated polyester resin having a softening temperature of 70 to 110°C and containing α and β unsaturated dicarboxylic acid and isophthalic acid as acid components, and α and β unsaturated dicarboxylic acid. and softening temperature 7 with terephthalic acid as the acid component.
A method for producing an impact-resistant molding material, characterized in that it is a mixture with 20-5% by weight of a terephthalic acid-based unsaturated polyester resin having a temperature of 0-110°C.