JPH0957774A - Manufacture of unsaturated polyester resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an unsaturated polyester resin composition which can be monufactured with a high operating efficiency by controlling the stickiness of a molding material and can be molded even at a low temperature and under a low pressure. SOLUTION: A lubricant with a melting point of 40-150 deg.C amounting to 0.12-20 pts.wt. is added to 100 pts.wt. of unsaturated polyester resin, and these components are kneaded over the fusion of the lubricant by heat.

Description

Detailed Description of the Invention

[0001]

The present invention relates to a method for producing an unsaturated polyester resin composition, and more particularly, to a method for producing an unsaturated polyester resin composition used as a molding material in a compression molding method.

[0002]

2. Description of the Related Art A resin composition obtained by adding a filler, a release agent, a pigment, a thickener and the like to an unsaturated polyester resin is impregnated into a reinforcing fiber material such as glass fiber to form a sheet or a bulk. The unsaturated polyester resin molding material is called a sheet molding compound (SMC) or a bulk molding compound (BMC). SMC and BMC are mainly compression molded and widely used for housing equipment, industrial parts or automobile parts.

These molding materials are often compression molded under heating. However, in the compression molding method, if the application products are to be expanded (increased in size and diversified), it is necessary to secure a large-sized molding machine, and it is necessary to invest a large amount of molds. Very large.

Conventionally, the compression molding temperature is 120 to 16
It is said that the compression molding pressure is 0 to 100 kg / cm ^{2 at} 0 ° C., but if the compression molding can be performed at a lower temperature and a lower pressure,
The cost burden can be reduced.

However, in the conventional method, if compression molding is simply performed at a low temperature and a low pressure, it is easy to cause a wall thickness, a cavity or a pinhole on the surface of the molded product. The nests and pinholes not only impair the appearance of the molded article, but also adversely affect the mechanical properties and durability of the molded article. Therefore, in order to reduce these inconveniences, material techniques have been devised.

For example, as disclosed in Japanese Patent Publication No. 60-16471, calcium hydroxide is used as a thickener to increase the fluidity under low pressure, the viscosity is reduced, and the viscosity of the molding material is reduced. Attempts have been made to lower However, this method has a drawback that the mold material tends to be sticky, so that the mold release property of a release film such as a polyethylene film covering the mold material and the workability such as cutting are reduced. Moreover, cavities and pinholes were likely to occur on the surface of the molded product.

Therefore, the inventors of the present invention have considered that it is possible to suppress the stickiness of the molding material by adding a lubricant such as an aliphatic alcohol, and as a result of investigation, the stickiness can be suppressed and the low temperature low pressure molding can be performed. I found it possible.

However, most of such lubricants are powdery or granular, and when used in SMC and BMC, the dispersion of the lubricant was insufficient and the performance was likely to vary.

[0009]

The object of the present invention is to provide a molding material comprising an unsaturated polyester resin composition,
It is an object of the present invention to provide a method for producing an unsaturated polyester resin composition capable of suppressing the stickiness of a molding material, thus having excellent workability, and capable of molding a molded product having little performance variation even at low temperature and low pressure.

[0010]

The present invention has been made in order to achieve the above-mentioned object, and 0.1 to 20 parts by weight of a lubricant having a melting point of 40 to 150 ° C. is added to 100 parts by weight of an unsaturated polyester resin. Part is a method for producing an unsaturated polyester resin composition, characterized in that the parts are kneaded while melting the lubricant by heating.

In the unsaturated polyester resin composition of the present invention, more specifically, in addition to the above unsaturated polyester resin and lubricant, preferably, the average particle size is 0.1 to 10.
0 μm of inorganic filler particles are unsaturated polyester resin 1
It is mixed in a proportion of 50 to 350 parts by weight with respect to 00 parts by weight. Further, preferably, a curing agent, a release agent, a thickener, a pigment, and the like are further mixed, and the kneaded unsaturated polyester resin composition contains reinforcing fibers so as to account for 2 to 40% by weight of the whole. Added.

The unsaturated polyester resin composition of the present invention can be formed into a sheet or a bulk. The sheet-shaped molding material is called SMC or TMC and is molded using a known machine. At this time, the unsaturated polyester resin composition excluding the reinforcing fibers is kneaded and stirred in advance with a device such as a stirrer. At that time, the lubricant is stirred while being melted. Upon melting, the entire kneading vessel may be heated with an oil bath, hot water bath or heater.

For example, in the case of SMC, an unsaturated polyester resin composition is applied on a release sheet such as a polyethylene film with a doctor blade to a uniform thickness, and reinforcing fibers are sprinkled on the surface, and the same procedure is followed. The reinforcing fiber may be sandwiched with the unsaturated polyester resin composition applied to the release sheet prepared as above, and the unsaturated polyester resin composition may be impregnated into the reinforcing fiber using a roll to form a sheet.

The bulk molding material is called BMC and is obtained by mixing with a mixer such as a kneader. During this mixing, the lubricant can be melted by forming the molding material while heating the entire kneader with a heater or the like.

However, in any case, the heating temperature must be above the melting point of the lubricant and below the temperature at which the above-mentioned curing agent begins to act. Further, the heating temperature is equal to or higher than the melting point of the lubricant (melting point + 10
C.) is preferably within the following range. Further, when the melting point of the lubricant is higher than the action temperature of the curing agent, it is preferable to remove the curing agent and knead by heating, and after cooling, add the curing agent and knead again. The maturing material is usually aged for half a day to 2 days,
This is done by placing the material under temperature conditions of 30-50 ° C.

Lubricant The lubricant used in the present invention is used to improve the fluidity of a generally known thermoplastic resin when it is hot-molded. Those that have an effect are broadly included. Specifically, as the lubricant, monohydric aliphatic alcohol, sorbitan fatty acid ester, higher alcohol higher fatty acid ester,
Examples include neopentyl polyol fatty acid ester and fatty acid amide. Details are shown below.

(A) Monohydric Aliphatic Alcohol A compound in which one hydrogen of a saturated or unsaturated aliphatic hydrocarbon is substituted, having 10 to 26 carbon atoms and a melting point of 4
The thing of 0-100 ° C is preferred. Specific examples include cetyl alcohol, stearyl alcohol, behenyl alcohol and the like.

(B) Sorbitan fatty acid ester A compound obtained by esterifying sorbit (molecular formula C ₆ H ₁₄ O ₆ ) with a fatty acid, which is esterified with a fatty acid having 8 to 26 carbon atoms and having a melting point of 40 to 100 ° C. Is preferred. Specific examples include sorbitan palmitate, sorbitan stearate, sorbitan tribehenate and the like.

(C) Neopentyl-based polyol fatty acid ester Neopentyl glycol, neopentyl triol or neopentyl tetraol, which is esterified with fatty acid, or these neopentyl polyols are linked by an ether bond. It is a compound obtained by esterifying a dimer with a fatty acid as a polyol component, and as the fatty acid, a compound in which hydrogen bonded to a terminal carbon of an aliphatic hydrocarbon having 10 to 25 carbon atoms is replaced with a carboxyl group is used. As a specific example,
Examples thereof include stearic acid ester of pentaerythritol, behenic acid ester of pentaerythritol, stearic acid ester of dipentaerythritol, and behenic acid ester of dipentaerythritol.

(D) Higher alcohol higher fatty acid ester A higher alcohol and a higher fatty acid are esterified, and a higher alcohol is obtained by substituting a terminal hydrogen of an aliphatic hydrocarbon having 10 to 36 carbon atoms as a higher alcohol with a hydroxyl group. An esterified product of an aliphatic hydrocarbon having 10 to 36 carbon atoms in which the terminal hydrogen is replaced with a carboxyl group is used. Specific examples include stearyl stearate, behenyl behenate, cetyl myristate, and the like.

(E) Fatty acid amide An amide derived from an ammonia or amino compound and a fatty acid, and as the fatty acid, preferably, an aliphatic hydrocarbon having 10 to 36 carbon atoms in which the terminal hydrogen is substituted with a carboxyl group. Used. Specific examples thereof include stearic acid amide, behenic acid amide, ethylene bis stearoamide, ethylene bis (hydroxy stearoamide), ethylene bis oleic acid amide, and ethylene bis erucic acid amide.

Any of the above lubricants, either alone or in combination with 100 parts by weight of the unsaturated polyester resin, can be used in an amount of 0.
It is added in a proportion of 1 to 20 parts by weight. Preferably 0.5
１５15 parts by weight. When the proportion of the lubricant is less than 0.1 parts by weight, the fluidity during molding is lowered, and when it is more than 20 parts by weight, cavities and pinholes are likely to occur on the surface of the molded product.

The lubricant has a melting point of 40 to 150.
Good at ℃. When the melting point is lower than 40 ° C, the handling property of the material before molding is lowered, and when it is higher than 150 ° C, the fluidity at the time of molding is lowered.

Unsaturated Polyester Resin The unsaturated polyester resin is an unsaturated polyester obtained by polycondensing an unsaturated dibasic acid, a glycol and, if necessary, a saturated dibasic acid, a polymerizable monomer, and a necessary monomer. And a thermoplastic resin for reducing shrinkage added by the above method.

As the unsaturated dibasic acid, maleic anhydride,
Fumaric acid, itaconic acid, citraconic acid and the like are used.
As the glycol, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, 1,3-butanediol, 1,4-butanediol, 1,6-hexanediol, bisphenol A,
Hydrogenated bisphenol A, ethylene oxide adduct of bisphenol A, neopentyl glycol, and the like are used.

As the saturated dibasic acid, phthalic anhydride, orthophthalic acid, isophthalic acid, terephthalic acid, adipic acid, succinic acid, tetrachlorophthalic acid, het acid and the like are used.

As the polymerizable monomer, styrene, dichlorostyrene, vinyltoluene, vinyl acetate, methacrylic acid, methacrylic acid ester, acrylic acid, acrylic acid ester, diallyl phthalate and the like are used, but styrene is preferably used. To be done.

As the thermoplastic resin for reducing the shrinkage, for example, polystyrene, polyvinyl acetate, polymethyl methacrylate, polyethylene, poly ε-caprolactone, saturated polyester, polyvinyl chloride, polybutadiene, polystyrene-acrylic acid copolymer Polymers, polystyrene-polyvinyl acetate copolymers, ethylene-vinyl acetate copolymers, vinyl chloride-vinyl acetate copolymers, acrylonitrile-styrene copolymers and the like are used.

As the inorganic filler fine particles added to the unsaturated polyester resin composition of the present invention as needed, calcium carbonate, aluminum hydroxide, calcium sulfate, glass powder, talc, mica, etc. are used. To be done. The particle size of the inorganic filler fine particles is preferably 0.1.
To 100 μm, more preferably 0.5 to 60 μm
m. If it is less than 0.1 μm, the viscosity of the composition becomes large, the reinforcing fibers are not sufficiently impregnated, air is easily mixed into the material, and the molded product is likely to have cavities. on the other hand,
If it is larger than 100 μm, the specific surface area of the particles becomes small, so that the viscosity of the composition becomes small and the handleability becomes poor.

Whether the inorganic filler is used alone or in combination, it is preferably in the range of 50 to 350 parts by weight, more preferably 60 parts by weight, based on 100 parts by weight of the unsaturated polyester resin. ˜300 parts by weight. If it is less than 50 parts by weight, the handling property of the material before molding may be deteriorated. Also, if it is more than 350 parts by weight, the viscosity will greatly increase, the fluidity at the time of molding processing will decrease, and the impregnating property with the reinforcing fiber will decrease, making it easy for air to mix into the material and forming a cavity in the molded product. May become easier to enter.

Further, as the reinforcing fiber added as required, glass fiber, carbon fiber, asbestos fiber, whiskers, organic synthetic fiber, natural fiber and the like are used. Glass fiber is preferably used in terms of physical properties and price. In addition to the case where a fiber having a fixed length or continuous fibers is used as it is, a mat-shaped or cloth-shaped fiber is also used. For example, in the case of glass fiber, a chopped strand obtained by cutting a strand to a predetermined length, a chopped strand mat formed by bonding a chopped strand with a binder to form a mat, and the like are used. As a fiber having a fixed fiber length, a fiber having a length of 1 to 80 mm is usually used. If it is shorter than 1 mm, there is no reinforcing hardening, and if it is longer than 80 mm, the viscosity may increase and the moldability may deteriorate. In addition, the directionality of the fibers in the unsaturated polyester resin composition is not limited to randomization, but may be arbitrary, such as one arranged in one direction, one arranged in an X shape.

The amount of the reinforcing fiber is preferably, based on the whole unsaturated polyester resin composition containing the reinforcing fiber,
It is mixed in the range of 2 to 40% by weight, more preferably 3
３５35% by weight. If the amount is less than 2% by weight, the handling property of the material is deteriorated, the reinforcing effect is not exerted, and the molded product is easily cracked and bent. When it is more than 40% by weight, the viscosity is increased and the fluidity is deteriorated.

Further, as a curing agent added as required, tertiary butyl peroxyisobutyrate, tertiary-butyl peroxy 2-ethylhexanoate, tertiary amyl peroxy 2-ethylhexanoate, 2,4,4-Trimethylpentylperoxy 2-ethylhexanoate, tert-butyl peroxypivalate, tert-butyl peroxybenzoate, tert-butyl peroxyisopropyl carbonate, tert-butyl peroxy 3,5
Organic peroxides such as 5-trimethylhexanoate, 1,1-bis (tert-butylperoxy) 3,3,5-trimethylcyclohexane, benzoyl peroxide, methyl ethyl ketone peroxide, cumene hydroperoxide are used. .

As the release agent, zinc stearate, stearium thermistor calcium, etc. are used. As the thickener, magnesium oxide, magnesium hydroxide, calcium oxide, zinc oxide or the like is used.

Unsaturated polyester resin composition as described above
The product is used in the compression molding process to obtain a molded product.
It is. For example, place the book in a mold heated to 60-120 ℃.
Injecting the unsaturated polyester resin composition of the invention in the required amount,
Molding pressure 2-30kg / cm ²Compression molding with. Preferred
The mold temperature is 80 to 110 ° C, and the molding pressure is 5 to 20.
kg / cm²It is said. Mold temperature is lower than 60 ℃
Flowability during shaping is reduced, and molding time is significantly increased.
I have something to do. If the temperature is higher than 120 ° C, the cost will be low.
Since it is not possible to use this type, it reduces the capital investment burden.
Can not be. Molding pressure is 2kg / cm²Less than
Fluidity decreases and the desired molded product is obtained.
Sometimes difficult, 30kg / cm²The larger the
Because the strike type cannot be used, the capital investment burden
Cannot be reduced.

The action in the present invention, with respect to 100 parts by weight of the unsaturated polyester resins, alone melting point 40 to 150 ° C. lubricant, or in combination with 0.1 to 20 parts by weight of unsaturated polyester resin composition kneaded Then, when uniformly dispersing, the lubricant is kneaded while being melted by heating. Commercially available lubricants are granular or powdery, but in the present invention, since they are kneaded and dispersed while being melted during kneading, they are better dispersed in a state closer to the molecular level, resulting in an unsaturated polyester resin composition. The uniformity of the product is improved.

Therefore, when the unsaturated polyester resin composition of the present invention is used to obtain a molded article by compression molding, the lubricant is uniformly dispersed, so that a molded article with less performance variation can be obtained. In addition, the lubricant enhances the wettability of the interface between the inorganic material and the resin, and the "slip" between the composition and the molding die.
It is considered that the fluidity at the time of low-temperature low-pressure molding is significantly increased.

[0038]

Example 1 45 parts by weight of an unsaturated polyester composed of fumaric acid, isophthalic acid and propylene glycol, and polystyrene 2
0 part by weight was melted in 35 parts by weight of styrene monomer to obtain 100 parts by weight of unsaturated polyester resin.

With respect to 100 parts by weight of the above unsaturated polyester resin, 140 parts by weight of calcium carbonate having an average particle diameter of 2 μm, 1 part by weight of tertiary butyl peroxyisobutyrate as an organic peroxide, and 0.03 part by weight of hydroquinone. Further, 5 parts by weight of cetyl alcohol (melting point 40 ° C.) as a lubricant was added and kneaded while being melted in a water bath at 45 ° C. for 30 minutes in advance to obtain an unsaturated polyester resin composition.

After adding 0.7 part by weight of magnesium oxide to the above unsaturated polyester resin composition and kneading, the glass chopped strands of 25 mm were impregnated using an SMC manufacturing apparatus, and the content of the glass chopped strands was 2% of the total.
0% by weight, covered with polyethylene film, SMC (thickness = 2 mm, width = 550 mm, length = 1
0 m), and this was wound into a roll.

The SMC was aged at 40 ° C. for 24 hours. Since the performance of the SMC varies depending on the place in the roll, that is, the position in the length direction, as shown in FIG. 1, the first part A to the fourth part when the SMC sheet is pulled out from the SMC roll. Four mini baths (size of 500 × 500 × 300 mm) were molded by the compression molding method using the part D (1 m in length). The molding conditions were such that the molding pressure was 5 kg / cm ² , the mold temperature was 90 ° C. for both males and females, 2.3 kg of SMC was charged into the mold, and the pressurizing time was 7 minutes.

Example 2 Sorbitan stearate (melting point 52-58 as a lubricant
C.) was used, and an unsaturated polyester resin composition was obtained in the same manner as in Example 1 except that the temperature of the hot water bath at the time of kneading was 60.degree.

Comparative Example 1 An unsaturated polyester resin composition was obtained in the same manner as in Example 1 except that the kneading was performed without heating and cetyl alcohol was not melted. I got the goods.

Comparative Example 2 An unsaturated polyester resin composition was obtained in the same manner as in Example 2 except that the sorbitan stearate was not melted and not heated during kneading, and compression molding was carried out in the same manner. A molded product was obtained.

Comparative Example 3 An unsaturated polyester resin composition was obtained in the same manner as in Example 1 except that the compounding amount of cetyl alcohol was 0.05 parts by weight, and compression molding was carried out in the same manner to obtain a molded product. Obtained.

Comparative Example 4 An unsaturated polyester resin composition was obtained in the same manner as in Example 1 except that the amount of cetyl alcohol was 30 parts by weight, and compression molding was performed in the same manner to obtain a molded product. .

Comparative Example 5 An unsaturated polyester resin composition was obtained in the same manner as in Example 1 except that no lubricant was added and heating was not performed during kneading, and compression molding was performed in the same manner. A molded product was obtained.

Regarding Examples 1 and 2 and Comparative Examples 1 to 5, S
The handleability of MC was evaluated by the presence or absence of sticky feeling on the surface. In addition, the charging area ratio of the SMC to the mold was evaluated from the obtained molded body according to the following procedure.

Charge area ratio (%) of molded body: The ratio of the projected area of the portion which was actually filled with the molding material to the projected area of the portion of the above-mentioned mold for molding the mini bath which should be in contact with the molding material. It was calculated as the charge area ratio of the molded body and used as an index of the fluidity of the molding material.

Further, the surface of each of the obtained molded products was visually observed to evaluate the presence or absence of cavities. The results are shown in Table 1 below. In addition, A to D below the charged area ratio in Table 1 means the first to fourth portions A to S in each SMC roll.
The charge area ratio in the molded body obtained by molding using D is shown.

[0051]

[Table 1]

In Table 1, Example 1 and Comparative Example 1 are
Alternatively, by comparing Example 2 with Comparative Example 2,
It can be seen that the heat kneading can eliminate the variation in the fluidity of the SMC (charge area ratio of the molded body).

In Example 1 of Table 1, the blending ratio of the lubricant was 5 parts by weight with respect to 100 parts by weight of the unsaturated polyester resin. In Comparative Examples 3 and 4, the blending ratio of the lubricant was 0. Maybe because it is 05 and 30 parts by weight, Comparative Example 3
In Comparative Example 4, the molded product obtained in Comparative Example 4 had a low charged area ratio, and in the surface of the molded product obtained in Comparative Example 4, the charged area ratio was as high as 100%. It can be seen that there are no nests. Therefore,
As is clear from the results of Example 1 and Comparative Examples 3 and 4, it is understood that the lubricant needs to be blended in the above specific range with respect to 100 parts by weight of the unsaturated polyester resin.

[0054]

As described above, according to the present invention, the lubricant is blended with the unsaturated polyester resin in the above-mentioned specific ratio, and when the lubricant is mixed with the unsaturated polyester resin, the melting point of the lubricant is The mixing is performed while heating at a higher temperature. Therefore, since the lubricant is uniformly dispersed in the unsaturated polyester resin composition, the lubricant is sufficiently and uniformly dispersed in the unsaturated polyester resin even when a commercially available granular lubricant is used. be able to.
Therefore, due to the effect of the lubricant compounded as described above, it is possible to suppress the sticky feeling of the molding material made of the unsaturated polyester resin composition, and thus the workability of the molding material can be improved and the workability can be improved. Since the fluidity under low pressure can be enhanced without damage, it is possible to obtain a high-quality molded product in which cavities and pin poles are less likely to occur by low-temperature low-pressure molding.

[Brief description of drawings]

FIG. 1 is a perspective view showing an SMC pulled out from an SMC core in an embodiment.

[Explanation of symbols]

 1 ... SMC roll

Claims (1)

[Claims] 1. An unsaturated polyester resin characterized by mixing 0.1 to 20 parts by weight of a lubricant having a melting point of 40 to 150 ° C. with 100 parts by weight of the unsaturated polyester resin while melting the lubricant by heating. A method for producing a composition.