JPS6022605B2 - Manufacturing method of SMC - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing SMC capable of forming a marble pattern.

In recent years, artificial marble made from synthetic resin has been used for bathtubs, washstands,
It is used for kitchen countertops, etc., but most of it is done by hand and has poor productivity. Recently, the thermo-pressure molding method using SMC, which is mechanized and capable of mass production, has become popular for glass fiber reinforced plastic (FRP) products, but the purpose of the present invention is to provide a method for manufacturing SMC that can form a marble pattern. . SMC is a sheet molding compound, which is usually a resin mixture made of unsaturated polyester resin containing chemical thickeners such as Mg0, fillers, colorants, low shrinkage agents, hardeners, molding agents, etc. A sheet-shaped molding material made by impregnating glass mat or glass roving into cut glass fibers, defoaming and thickening the material.Both sides are covered with a thermoplastic film, which is peeled off before use.

This material is used to mold parts with lips and boss structures, and the molding conditions are generally 14,000, 50 to 150 k9/2, 3
~5 minutes. When patterning is attempted by hot-pressing molding using SMC, the most problematic problem is the inhibition of patterning due to the high fluidity of SMC during hot-pressing.

Conventionally, colored SMCs with two or more different hues are created, and then placed on a mold and pressed. Alternatively, in the process of making SMCs, colored SMCs are dotted in advance with a compound' coloring material. Sprinkle glass on S
Methods such as making MC and pressing it have been considered, but all of them have been unsatisfactory as the pattern becomes blurred and unclear due to excessive flow during pressing.

In order to prevent excessive flow of the pattern-forming material, various aspects such as the form and physical properties of the pattern-forming material itself, the relative position of the base SMC and the pattern-forming material, and the state in which the pattern-forming material is added to the base SMC must be considered. It was recognized that consideration was necessary. It is desired that these be done in a manner that does not impede productivity, workability is reasonable, and does not adversely affect the physical properties of the product. As a result of various studies, the present inventors found that a normal SM
In the C manufacturing process, glass fibers are dispersed at least twice, and a pattern forming material made of a colored filler with a particle size of 50 to 300 particles is placed in between, and this is degassed and thickened using a conventional method. It has been discovered that by processing the SMC sheet to create an SMC sheet and press-molding this, the flow of the pattern-forming material can be appropriately controlled and a molded product having a marble pattern with an excellent color tone can be obtained.

First, how to make the SMC material in the present invention will be explained based on the drawings.

In the drawing, 1 is an endless belt conveyor. First, the base SMC resin compound 2 is applied onto the film 3 using, for example, a doctor blade method. Subsequently, the glass roving 4 is cut into a predetermined length using a roving cutter 6 and scattered thereon. Next, the pattern forming material 6 is sprinkled onto the cut glass by the pattern forming material spreading machine 7. Furthermore, a predetermined amount of glass roving 4' is scattered thereon while being cut into a predetermined length with a cutter 5'. Finally, the base SHC resin compound 2' is applied onto the film 3' and superimposed, and then impregnated and defoamed with a defoaming roll 8. In this way, a resin-impregnated sheet 9 containing the pattern-forming material in the glass layer is obtained, and this is aged to obtain the SMC of the present invention. The method of the present invention involves dividing the glass fibers into at least two locations, whereas glass fibers are normally dispersed at one location in SMC production, and forming a pattern-forming material consisting of a colored filler with a predetermined particle size at a location between the two locations. is arranged so that it is wrapped in glass fiber.

We have found that by using such SMC, it is possible to appropriately control the flow of the pattern forming material during press molding, as will be described later. In this method, excessive flow of the pattern forming material can be suppressed and properly controlled by pre-positioning the colored filler with an appropriate particle size so that it is wrapped between the glass fibers. This is thought to be due to the fact that glass fibers act as a filter when the SMC material flows, suppressing the diffusion of coloring components. In order to exhibit such an effect, it is not preferable that the particle size of the colored filler serving as the pattern forming material be less than 50 mm because it is too fine and will pass through the glass fibers and diffuse too much. Furthermore, pigments and dyes that are less than the number used as conventional general coloring raw materials are unsatisfactory. Further, if the number of peaks is increased to 300 or more, the filter effect will increase, but if colored components appear on the surface of some products, they will look like spots, which is not preferable. A preferred range is an average particle size of 50 to 300 grains. SMC of such pattern forming material
The relative addition location within the material requires that it be placed between the glass fibers so that it is wrapped in the glass fibers.

If placed on the surface of the SMC sheet, the filter effect of glass fibers will not be exhibited, and the pattern forming material will be excessively diffused along the mold surface during molding, making the pattern unclear and making it impossible to achieve the purpose. Can not. Next, the preferred specific shape of the pattern forming material will be described.

As a pattern forming material, the above-mentioned colored filler of 50 to 300 colors is used i. It is used in powder form.ii. It is used as a paste by kneading with unsaturated polyether resin etc. 111 Base SMC
The resin mixture of iv i8 is mixed with an unsaturated polyester resin containing a thickener and used as a non-tacky sheet after being thickened, like a resin mixture for use in plastics, and is supported on a base material such as glass fiber. There are methods such as using it as a sticky sheet.

These pattern forming materials i) to iv) are dispersed in an appropriate shape, size, and distribution. Here, method i) tends to cause defective defoaming during the SMC defoaming process, and method h) may cause the pattern to spread during the impregnation defoaming process using rolls, so it is not the preferred method, but it is possible if handled properly. It is. The most preferred forms are range) and iv). By forming SMC into a non-adhesive sheet in advance (bait), it is easier to spread it during the SMC manufacturing process, and it is more effective in preventing the pattern from spreading during the defoaming process or the subsequent pressing process. In this way, the colored fillers that serve as the base of the pattern forming material include, for example, inorganic colored mineral powders such as mica powder and red iron powder, dyed colorless mineral fillers, or ordinary pigments of several micrometers or less. There are also those obtained by crushing cured resin products colored with dyes.

In particular, mica powder has a deep color tone that is a natural product, and also has a moderate transparency, and is used as a pattern-forming material color and can give a superior texture compared to general pigments with large hiding properties. It goes without saying that the shape (plate-like, rod-like, belet-like, etc.), size, distribution, etc. should be appropriately selected according to preference. Next, preferred conditions for the base SMC will be described.

Normally, SMC is made from a mixture of unsaturated polyester resin with fillers, thickeners, coloring pigments, low shrinkage agents, hardening agents, etc., but it is opaque due to the fillers and coloring pigments. Complete opacity is not suitable for marble-patterned objects because it cannot create depth or texture. Therefore, in the present invention, no pigment is used in the resin formulation for the base SMC, or if it is used, it is used in as little amount as possible, and as a filler, a pigment with a refractive index of 1.57, which is close to 1.55 of polyester resin, is used as a filler. By blending 30 to 120 parts, preferably 50 to 10 parts, of hydrated alumina with a grain size of 10 to 30R, the translucent feel of marble can be obtained, and by combining it with the above-mentioned patterning. You can get the beautiful texture of marble. In order to achieve transparency by mixing a filler with a resin, it is necessary to use a filler with a refractive index similar to that of the resin. Examples of this include hydrated alumina and silica glass powder, which have a refractive index of 1.5. ~1.6. Particle size also affects transparency, with particles less than 10 being shielding, and particles less than 30 being shielding.
Above Buddha level, it contributes to transparency, and 10 to 30 peaks show translucence/transparency. Due to the influence of various additives, SMC has difficulty achieving transparency and is limited to semi-transparency. A blend of 30 to 12 fillers is in a range that exhibits translucency. The above will be explained in more detail based on examples.

Example 1 (parts indicate parts by weight) [Creation of pattern forming material] Unsaturated polyester resin 10 mica powder (brown,
Suzorite 8$, manufactured by Kuraray, particle size approximately 200r) 5
A compound is made by adding a thickener (Mg○), a low shrinkage agent, a mold release agent, and a hardening agent, and this is made into a sheet with a thickness of 2 and aged at 400 qo/4 pongee to create a pattern. A forming material was created.

[Creation of resin mixture for base SMC]

10 parts of unsaturated polyester resin, hydrated alumina (Hygilite Ni-31, trade name manufactured by Showa Denko, particle size approximately 15 m2)
A thickener (manufactured by M), a low shrinkage agent, a template agent, a hardening agent, etc. were added and mixed well to prepare a base SMC resin mixture.

[Creation of SMC containing pattern forming material]

The resin mixture for base SMC was coated with a doctor blade for 1000 coats on a polyethylene film having a thickness of 1.5 mm, which was continuously running on a belt comparer.

Next, glass roving (FfGIO-17
(trade name, manufactured by Fuji Fiberglass Co., Ltd.) was cut into 25 side lengths with a roving cutter and sprayed on the pillow for 250 minutes/pillow.
Next, place the pattern forming material sheet 20x20x5x50x
While cutting the table, I sprayed it on the first layer of glass at a rate of 1 for every 100 rocks. Subsequently, glass roving was sprinkled with the same specifications as the first layer.

Furthermore, a resin mixture for base SMC was coated on a polyethylene film with a Dr. Frederic coater for 1000 coats per coat, and then the glass surface was overlapped with the resin mixture, and then the resin was thoroughly impregnated and defoamed using a defoaming roller. The thus obtained sheet was aged for 40 qo/4 rs to thicken it, and an SMC in which the pattern forming material was included between the glass fiber layers was created. [
Press Molding] This SMC was cut into an appropriate size, and placed on a mold in exactly the same manner as a normal molding method, and a bathtub was molded at a molding temperature of 140° C., a pressure of 100 k9/average, and a time of 5 minutes.

As a result, a molded article with an excellent marble pattern with a very deep color tone was obtained.

Since the SMC obtained by the present invention can be realized by adding relatively simple operations, it is useful as a method for mass-producing molded products with a marble pattern.

Furthermore, by appropriately selecting the color, shape, etc. of the pattern forming material, it is possible to respond to the diversified preferences of users.

[Brief explanation of the drawing]

The drawing schematically represents a manufacturing apparatus for marble-patterned SMC. Explanation of symbols, 1...Inorganic belt conveyor, 2, 2'
...Polyester resin mixture, 3,3'...Thermoplastic resin film, 4,4'...Glass roving, 5
, 5'... Roving cutter, 6... Pattern forming material, 7...
・Pattern forming material spreader, 8... Defoaming roll, 9...
Aged SMC sheet.

Claims (1)

[Claims] 1 (a) A thermoplastic film carrier having a refractive index of 1.5.
~1.6 and a step of coating a base SMC resin mixture containing an inorganic filler with an average particle size of 10 to 30μ. (b) Spreading a predetermined amount of glass roving while cutting it into a desired length. (c) A step of dispersing a pattern forming material processed into a desired shape and size and containing a colored filler with a particle size of 50 to 300 μm. (d) Spreading a predetermined amount of glass roving while cutting it into a desired length. (e) Coating the same resin mixture as used in (a) onto the thermoplastic film carrier and superimposing it on the glass layer. A method for manufacturing SMC, characterized in that the sheet obtained by successively performing the steps (a) to (e) above is defoamed and thickened. 2. Claims in which the pattern forming material is made by mixing a colored filler with a particle size of 50 to 300 μm into an unsaturated polyester resin containing a thickener, thickening the mixture, and processing the mixture into a desired shape and size. A method for producing SMC according to item 1. 3. The method for producing SMC according to claim 1 or 2, wherein the colored filler having a particle size of 50 to 300 μm is mica powder.