JP2884216B2 - Manufacturing method of resin molding material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for agitating a resin raw material which enables press molding even of an acrylic resin raw material and a method for producing a bulk molding compound (hereinafter referred to as BMC) which is a resin molding material thereof. It is.

[0002]

2. Description of the Related Art As methods for producing artificial marble, there are molding by hand lay-up, press molding, and cast molding. The band lay-up method involves a worker sequentially laminating a gel coat, a resin material, glass fibers, and the like on the surface of a molding die, and is not suitable for mass production because the worker manually works.

[0003] On the other hand, press molding involves the use of a resin material and
An SMC (sheet molding compound) as a resin molding material in which a filler and a glass fiber are prepreg, and the above-mentioned BMC are placed in a molding space of a heating mold, and are heated and cured simultaneously with pressure molding at a high pressure. It is. This press molding is characterized by a short molding cycle, excellent production capacity, and suitable for mass production.

However, the SMC used for press molding
And BMC need to have a certain degree of high viscosity. When the viscosity is low and soft, when press-molding with a heating mold, only the resin material spreads and fills the molding space, and the filler and glass fibers as aggregates are separated into beads and separated, resulting in defective products. Because it becomes. Further, in this press molding, only a thin product can be formed, and it is impossible to produce a thick product having a high quality feeling.

[0005] Cast molding is a method in which a resin material, a filler and glass fiber are poured into an open mold or a mold by a predetermined thickness and dried and solidified by a polymerization reaction under normal pressure to produce a product. . In this cast molding, the thickness of the product can be considerably increased, so that it is possible to manufacture a product with a high-class feeling. However, in this cast molding, since the molding is performed under normal pressure, the molding cycle becomes extremely long, which is not suitable for mass production.

[0006]

On the other hand, when viewed from the viewpoint of resin raw materials, unsaturated polyester resins are both inexpensive and suitable for mass production, and both high-quality cast molded products and high-quality cast molded products. Can be formed. However, in the case of an acrylic resin widely used as a resin material, only cast molding is possible, but press molding is not possible.

[0007] As described above, this is because the resin material, the filler and the glass fiber, etc. are separated at the time of the press molding unless the resin material has a viscosity higher than a certain level in order to perform the press molding. This is because it becomes a ball and becomes a non-uniform defective product. In the case of an acrylic resin, it is impossible to secure a high viscosity necessary for press molding.

[0008] The reason is that, in the case of an unsaturated polyester resin, a carboxylic acid is contained in the resin raw material, and when a thickener (MgO) is added, the carboxylic acid and MgO are ionically bonded (metal cross-linking). ) To increase the viscosity of the overall material. However, in the case of an acrylic resin, a carboxylic acid or the like for ionically bonding with the thickener is not present in the resin raw material, and the desired viscosity cannot be obtained using the thickener. .

Another reason that acrylic resin cannot be press-molded is that press molding is characterized by maintaining the molding temperature as high as 120 ° C., activating the reaction of the resin, and short-time molding. At such a molding temperature, since the acrylic resin has a boiling point of 100 ° C., it may evaporate as soon as the acrylic resin is filled into a molding die, making molding impossible.

It is also conceivable to lower the molding temperature so that the acrylic resin does not evaporate. However, in this case, the polymerization reaction of the resin requires a long time, the molding cycle becomes longer, and the characteristics of press molding are lost. However, there is a problem that only the same advantages as those obtained by the cast molding can be obtained.

Further, the conventional unsaturated polyester resin is thickened by adding MgO as a thickener separately from the resin raw material.
And the disadvantage that the carboxylic acid must be contained in the resin raw material. In addition, the ionic bond (metal cross-linking) between MgO and carboxylic acid has the disadvantage that the viscosity changes depending on the curing method and period, and the storage of the resin material becomes unstable.

[0012]

DISCLOSURE OF THE INVENTION The present invention has been made in view of the above-mentioned problems and has been improved and eliminated. The present invention relates to a resin molding material which is easy to handle and enables press molding even with acrylic resin. It does not provide a manufacturing method.

[0013] In order to solve the above-mentioned problems, the present invention adopts a method according to claim 1, which comprises heating and stirring a high-viscosity resin material, a filler, various additives, and a thickener. A method for producing a resin molding material, characterized by cooling to obtain a high-viscosity bulk material.

According to a second aspect of the present invention, which is adopted to solve the above-mentioned problem, the resin raw material in the first aspect is specified to be polyester or acrylic.

[0015]

According to the first aspect of the present invention, a high-viscosity resin material, a filler, various additives, and a thickener are stirred while being heated, and then cooled to produce a high-viscosity BMC. Like that. By using the thickener, both the conventional chemical thickening action (metal cross-linking) by the carboxylic acid in the resin raw material and MgO as the thickener, and the physical thickening action by heating and stirring are performed. And an excellent thickening effect can be obtained.

[0016]

Embodiment 1 Next, the method of the present invention will be described based on each embodiment described below. This Example 1 shows a chemical thickening effect of MgO as a thickener, which is a conventional technique,
The physical thickening effect by the heating and stirring of the first embodiment is obtained. Therefore, the acrylic syrup used in Example 1 needs to have a carboxyl group for performing metal crosslinking with the thickener, and an acrylic syrup material having an acid value is selected. The viscosity at room temperature of this acrylic syrup is 10,000 cps.

In the first embodiment, the following raw materials are prepared. That is, 100 parts by weight of acrylic syrup (with an acid value) 1 part by weight of curing agent 0.1 part by weight of polymerization inhibitor 200 parts by weight of aluminum hydroxide 3 parts by weight of thickener (MgO)

The range of the mixing ratio of the curing agent, the polymerization inhibitor and the aluminum hydroxide to 100 parts by weight of the acrylic syrup is the same as that of the first embodiment. The mixing ratio of the thickener (MgO) to 100 parts by weight of the acrylic syrup is 1 to 20 parts by weight.

Next, the prepared raw material is placed in a closed heating stirrer, heated to 50 ° C., and simultaneously with 1 kgf / c.
Mixing and stirring are performed by applying a pressure of m ² . If the stirring is performed while heating as described above, the temperature is set at 10,000 at room temperature.
Acrylic syrup having a viscosity of 0 cps and incapable of mixing and stirring decreases the viscosity to 1,000 cps, and enables mixing and stirring.

Further, by applying a pressure of 1 kgf / cm ² , it is possible to reduce the loss of the acrylic syrup due to the vaporization of the monomer component due to the heating. This is because, if the vaporized components are filled in the factory, the working environment will be deteriorated and the mixing ratio will be changed, which is not preferable. However, this pressurization is not always necessary and can be omitted. Further, the monomer component which evaporates in the closed vessel may be cooled to be liquefied and returned to the heating stirrer.

After mixing and stirring in this manner, a continuous molding material having a predetermined thickness is formed by an extruder, which is cut into a predetermined length to obtain a bulk resin molding material. Thereafter, the resin molding gradually obtains an ionic bond (metal cross-linking) between the carboxyl group contained in the acrylic syrup and MgO, and the viscosity sharply increases (chemical thickening action). At the same time, by naturally cooling from a heated state to room temperature, a physical thickening action is obtained, and a highly viscous molding material suitable for press molding can be obtained.

Incidentally, the present invention is not limited to the above-described embodiment, but can be appropriately changed. For example, in Example 1, it is possible to separately add swellable resin fine particles (crosslinked acrylic polymer) in the range of 1 to 2 parts by weight. The swellable resin fine particles have an action of swelling or partially dissolving due to the monomer component in the acrylic syrup, whereby the shrinkage of the entire material during curing can be reduced.

Although the case where MgO is used as the thickener has been described, other than Mg (OH) ₂ , Ca (OH) ₂ ,
CaO + Ca (OH) ₂ , CaO + MgO and the like are possible. Furthermore, the viscosity of acrylic syrup is 5,000 at room temperature.
Press molding can be performed by using a material of up to 20,000 cps. Further, the temperature of the heating and stirring is suitably in the range of 50 to 70 ° C. which can reduce the viscosity of the acrylic syrup to the range of 100 to 2,000 cps. 5-2Kgf / c
It may be carried out in the range of m ^2. Furthermore, the resin molded product may be a sheet-like SMC other than the bulk-like BMC.

[0024]

As described above, according to the present invention, a high-viscosity resin material, a filler, various additives, and a thickener are stirred while being heated, and then cooled to produce a high-viscosity BMC. Like that. Thereby, both the conventional chemical thickening action (metal cross-linking) by the carboxyl group in the resin raw material and MgO as the thickener, and the physical thickening action by heating and stirring can be obtained. An excellent thickening effect can be obtained. That is, a highly viscous resin raw material suitable for press molding can be obtained. This makes it possible to press-mold even an acrylic resin, and it is possible to dramatically improve the method of molding a resin product.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI B29B 15/10 B29B 15/10 // B29K 33:04 67:00 105: 12 (56) References JP-A-3-97759 ( JP, A) JP-A-7-125038 (JP, A) JP-A-6-91635 (JP, A) JP-A-63-78704 (JP, A) JP-A-62-204904 (JP, A) (58) ) Surveyed field (Int.Cl. ⁶ , DB name) B29B 7/00-17/02

Claims (2)

(57) [Claims] 1. A resin molding, wherein a high-viscosity resin material, a filler, various additives, and a thickener are heated and stirred, and then cooled to obtain a high-viscosity bulk material. Material manufacturing method. 2. A high-viscosity bulk material is obtained by heating and stirring a high-viscosity polyester or acrylic resin raw material, a filler, various additives, and a thickener, followed by cooling. Manufacturing method of resin molding material.