JPH01297465A - Molded synthetic resin article - Google Patents

Abstract

PURPOSE:To obtain the subject molded article having freely controllable transparency and excellent mechanical strength and suitable as cosmetic container, etc., by compounding a thermoplastic resin having high transparency with a specific amount of a matting agent such as glass beads or crosslinked polystyrene beads having specific particle size and specific refractive index. CONSTITUTION:A thermoplastic resin having high transparency (e.g., PS, AS, transparent ABS or PET) is compounded with 0.5-30wt.% of glass beads, crosslinked polystyrene beads, crosslinked acrylic resin beads, etc., having spherical shape of 3-600mum is diameter, high-resistance and transparency and exhibiting high refractive index (nD=1.3-2.7) or an arbitrary combination of the above beads.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention provides a method for making the surface of various transparent synthetic resin containers such as cosmetic containers and other transparent synthetic resin moldings matte (matte state). It relates to a synthetic resin molded product that is semi-transparent frosted glass-like or that diffuses light.

(Prior art) In bottle-shaped containers for storing cosmetics, the color of the cosmetics inside the container can be seen from the outside, and the surface of the container is covered with translucent frosted glass to enhance fashionability. Various types of synthetic resin containers have been commercialized, as well as synthetic resin moldings with surfaces processed to diffuse light to prevent light reflection, such as transparent panels for instruments related to vehicles and home appliances. has been done.

As mentioned above, as a means of forming a mat on the surface of a synthetic resin molded product, ■ The mold surface of the mold cavity is made with fine irregularities by sandblasting or electric discharge machining, and the molten resin is poured into the mold and cooled and solidified. 1) A method of mixing a predetermined amount of matting agent into the paint and spraying it onto the effective surface of the molding using an air gun, etc.;
■A method of blowing sand of any mesh onto the molded object with strong air force, forming unevenness with the sand particles, adhering to the molded object, blowing the sand with air, then washing and drying, ■Matte printing A method of transferring the plastic film onto a molded product using a hot rubber roll, or ■ Inorganic fillers such as highly heat-resistant calcium carbonate, zinc white, and glass fiber, or polyethylene, polystyrene, and MMA.
There is a method of blending organic beads such as organic beads into a molding material as a matting agent.

(Problem to be solved by the invention) However, if a mat is formed on a transparent synthetic resin molded product by the above method, the productivity is good with the method (2), but on the other hand, if the molding conditions are poor, unevenness may not be reproduced. It may deteriorate or the gloss may become uneven depending on the location of the product. Furthermore, when a small amount of air remains in the cavity, etc., the transfer accuracy of the entire mold surface deteriorates, causing unevenness of the mat. Furthermore, when the mold is released, it may easily rub off depending on the shape of the molded product, so it is not suitable for complex shapes and is limited to relatively flat shapes. Furthermore, there are many problems such as the unevenness of the molded product, which is easily damaged.
Furthermore, this method also makes it impossible to control the transparency of the molded product. In method (2), it is necessary to mask functional parts such as caps and screws before applying matte coating to the molded product, resulting in poor productivity and high costs. In addition, there are variations depending on each product, and there are many problems such as restrictions on printing and hot stamping. According to method ■,
After sand is blown onto the molded product, the blown surface is blown with air, washed with water, and then dried, which is time-consuming, reduces productivity, and increases costs. In addition, the surface of molded products processed by this method is easily damaged, and the quality is poor despite the high cost.

In method (2), thermal transfer is limited to surfaces with simple shapes such as the flat surface or circumference of the molded product, so it is only possible to apply matte partially to the product. In addition, due to superficial processing,
There are limits to the control of transparency. Furthermore, high pressure and heat are applied to the molded product during the processing process, which can cause distortion in the surface layer, which can later cause cracks. In method (2), when the matting agent blended is an inorganic filler, it has high heat resistance but has a flat or needle-like crystal shape, which has poor dispersibility and adhesion to the molding material, making it difficult to obtain a beautiful matte appearance. It tends to be hard and cause uneven matte. Furthermore, if a small amount is added to maintain the transparency of a molded article, the unevenness of dispersion becomes noticeable, and if the amount added is slightly increased, the hiding power becomes high and the object becomes opaque, making it difficult to control the transparency. In addition, especially when calcium carbonate is used as a matting agent, the gas generated by calcium carbonate causes the mold to rust, resulting in increased costs. On the other hand, when organic beads such as polyethylene or polystyrene 2MMA are used as a matting agent, the beads have good dispersibility and adhesion to the molding material, but the heat resistance is about 90°C to 100°C, and the molding material There is a problem in that when the beads are added to the matting agent, the beads dissolve and become useless as a matting agent.

The present invention has been made in view of the above problems, and includes:
The purpose is to determine the conditions for the matting agent added to the molding material (a)
This matting agent has good dispersibility in molding materials, (b) high heat resistance, and (c) no hiding properties even when the ffi is increased, and can give a matte feel even with a small amount. By arbitrarily blending the material, transparency can be controlled freely and a beautiful matte feel can be obtained, while mechanical strength such as surface hardness 1 bending strength is increased, and the surface of the molded product is resistant to stains and has a good texture. The purpose of the present invention is to provide a synthetic resin molded product.

(Means for Solving the Problems) In order to achieve the above object, the synthetic resin molded product of the present invention is made of a relatively transparent thermoplastic resin such as PSSAS, transparent ABS, etc., and has a spherical shape with a particle size of 3JJJR to 6001m. It has high heat resistance, is transparent, and has a sodium D line of 1.3 = 2.
．． Glass beads, crosslinked polystyrene beads, crosslinked acrylic beads, etc. exhibiting a high refractive index of 7 are used alone or in combination in an amount of 0.5 to 30% by weight. Moreover, this synthetic resin molded product is formed into various shapes for various containers such as cosmetics and various uses by injection molding, blow molding, extrusion molding, cast polymerization molding, etc.

The reason why glass beads, cross-linked polyethylene beads, cross-linked acrylic beads, etc. are used as matting agents in the present invention is that they are all fine, transparent, perfectly spherical particles with a particle size of 3 to 600 mm, and have excellent surface smoothness. , high surface hardness, good chemical resistance, and high refractive index ((nD=1°3~2.7
) Based on the fact that it has a matte effect, etc.

The reason for specifying the particle size of the above-mentioned matting agent in the range of 3 to 600 is that this range is not only easy to manufacture, but also provides a relatively uniform spherical shape with high surface hardness, and is suitable for resins. This is based on the fact that it has good dispersibility and high adhesion. Although particles with a particle size of less than 3 μm have good dispersibility with the resin, their surface area is small, so there is a problem with the adhesion strength with the resin. Furthermore, when the particle size exceeds 600 mm, the surface area increases and the adhesion strength to the resin increases, but the dispersibility in the resin deteriorates and the surface hardness of the beads themselves decreases.

In addition, since the above matting agent is transparent, the molded product will not become matte unless it exhibits a high refractive index, so nD=1
．． It is limited to those with a high refractive index of 3 to 2.7, but if the refractive index is too small, it will not be possible to obtain an effective matte on the molded product, and if the refractive index is too large, the transparency of the molded product will deteriorate. Based on things like getting lower.

Then, the blending ratio of the above-mentioned matting agent to the molded product is 0.5~
The reason for choosing the range of 30% by weight is that if the amount is too small, the molded product will not have a beautiful matte appearance, while if it is too large, the dispersibility and adhesion to the resin will be poor, and it will become opaque. This is taken into consideration.

(Example) Preferred embodiments of the present invention will be described below.

In the first example, 5% by weight of cross-linked polystyrene beads with a particle size of 11/ffl are blended into As resin, and the As resin containing the cross-linked polystyrene beads is formed by injection molding.The side wall thickness as shown in FIG. The foundation container 1 had a diameter of 765 mm and had a frosted glass appearance.

In the figure, 2 indicates the As resin after molding, and 3 indicates the crosslinked polystyrene beads.

The second example is a foundation container having the same shape as the first example and having a side wall thickness of 3.7 mm and formed in the same manner as the above example by blending 10% by weight of 11 μm cross-linked polystyrene beads in As resin. Its appearance is similar to that of the first embodiment (not shown). The molded product according to the third embodiment is a cap for a bottle-shaped container, and this cap consists of an outer cap and an inner cap. The outer cap is molded from a transparent material of MMA resin mixed with 5% by weight of cross-linked polystyrene beads with a particle size of 6.0 mm and 8% by weight of cross-linked acrylic beads with a particle size of 100 mm, and the one-way cap is molded from an opaque resin. When the inner cap was fitted to the outer cap, a matte appearance was obtained, and a unique appearance with light reflection properties was obtained. This is a particle size of ↑゛ which is blended with the MMA resin of the outer cap. OIJ! This is due to the :7t effect of the crosslinked polystyrene beads of R and the photorecurrence effect of the crosslinked alkali beads with a particle size of 100mm.

The molded article of the fourth embodiment is a compact container 4 as shown in FIG. 2, and the lid 5 of this compact container 4 consists of A portion and B portion of different colors.

Part A contains an As resin containing 0.009% by weight of anthraquinone violet dye and 0.0051% by weight of anthraquinone blue dye, and this As resin contains a particle size of 6.5%. O
It is molded by blending 8.0 mm% of 1m cross-linked polystyrene beads, and the B part contains 0.002% by weight of titanium oxide and 0.00003% by weight of anthraquinone violet dye in highly transparent As resin. It is molded by blending 4.0% by weight of glass beads with a particle size of about 60 in As resin.

Part A of the lid body 5 has a beautiful blue frosted glass appearance, and part B is milky white and has a mist-like appearance due to the light-reflecting effect of the glass beads, creating a design with two complex tones. An excellent compact container was obtained.

Note that when beads exhibiting a high refractive index, particularly near nD=2.0, are used in the B portion, the photoresynchronization effect appears more strongly.

In the fifth example, 15% by weight of cross-linked acrylic beads with a particle size of 15 pieces and 1 glass beads with a particle size of 100 μm were added to PET resin.
A molded product as shown in FIG. 3 was obtained by blow molding. In the figure, 6 indicates PET resin, 7 indicates cross-linked acrylic beads, and 8 indicates glass beads. When the parison is stretched during blow molding, the glass beads 8, which have large particle size and lack elasticity, will stretch together with the resin 7. The molded product is left behind, resulting in the condition shown in Figure 3, and the surface of the molded product has uniform irregularities due to the glass beads 8, and the thick part becomes frosted glass-like due to the crosslinked acrylic beads 7, giving it a unique appearance. It became.

Although several examples have been described above, the resins used for molding are not limited to the three types of examples above, but include PS,
It is possible to use thermoplastic resins such as MS, PVCSPC, and highly transparent olefin resins, and the blended matting agent has high heat resistance, is spherical, transparent, and has a high refractive index (nD = 1°7 ~2.3) As long as the particle size is in the range of 3 to 600 μm, the beads are not limited to the three types of beads in the above embodiments.

In addition, the synthetic resin molded product of the present invention can be made into containers and other various products by various molding methods such as injection molding, blow molding, extrusion molding, and cast molding.
Even if a specified amount of MA beads is mixed, depending on the molded product and molding conditions, many cross-linked M MA beads may be present on the surface of the molded product, making the surface uneven, or the surface may be glossy and the cross-linked MMA beads may be inside the thick wall. It is possible to disperse it and make it into a frosted glass shape.

In other words, to create irregularities on the surface as in the former case, injection molding should be performed at low injection pressure and injection speed, or blow molding or extrusion molding may be used to create more beads on the surface of the molded product. The beads form irregularities on the surface. In addition, in order to make the beads dispersed within the thickness of the molded product, as in the latter case, it is possible to mold the plate material by injection molding under conditions of high injection pressure and high injection speed, or by molding the plate material by cast polymerization molding. .

(Effects) As described above, the synthetic resin molded product of the present invention has PSLAS,
Comparatively transparent thermoplastic resin such as transparent ABS, glass beads, cross-linked polystyrene beads, cross-linked MMA beads, etc. are highly heat resistant, spherical, transparent, and have a sodium D line of 1.3.
Because it is formulated with a matting material that exhibits a high refractive index of ~2.7 and a particle size of 3 to 600 mm, the beads, which are the matting agent, have good dispersibility in the resin, making it possible to form molded objects. The appearance becomes a beautiful matte with no unevenness.

■Since the matte effect is due to the beads blended into the resin, the resin can be colored freely, and the transparency can be controlled by the amount of beads blended.

■In particular, the beads blended in this invention have a high refractive index and have a light re-reflective effect, so that when light enters the molded product, the light rays that entered at a certain angle pass through the beads and are reflected directly on the side. Some of the light rays reach the coloring material and are reflected, but some of the light rays are refracted and reflected by the beads, or are repeatedly refracted and reach the inner coloring material, and then refracted again and into the eyes, resulting in a blurred color tone. Therefore, by blending beads with different refractive indexes, it is possible to obtain different matte textures, resulting in a highly decorative and excellent design.

■Because the beads, which are matting agents, are hard, the surface hardness of the molded product is slightly improved, making it less likely to be scratched.

■ Fine, uniform spherical protrusions are formed on the surface of the molded product, resulting in streamlined irregularities, resulting in good sliding properties and a high rolling effect at the fitting part between the lid and container body of cosmetic containers, etc., improving operability. is planned.

(2) In addition, since the surface of the molded product has a streamlined uneven shape, it is difficult for dirt to adhere to the surface, and the adhered dirt is easy to remove, and it is smooth to the touch.

■It has excellent effects such as no effect on hot stamping or printing.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a container according to the first embodiment of the present invention, and FIG.
The figure is a perspective view of the compact container according to the second embodiment, and FIG. 3 is a partially enlarged sectional view of the formed product according to the fifth embodiment. 2...AS resin 3...Crosslinked polystyrene beads 6...
PET resin 7...Crosslinked acrylic beads 8...Glass beads Patent applicant Agent Yoshida Kogyo Co., Ltd.
Patent Attorney - Ken Sukedo Iro
Patent Attorney Masatoshi Matsumoto Figure 1 Figure 2 Figure 3

Claims (2)

[Claims] (1) Made of relatively transparent thermoplastic resin such as PS, AS, transparent ABS, or PET, the particles are spherical with a particle size of 3 to 600 μm, are highly heat resistant, transparent, and have a refractive index of 1.5 μm for the sodium D line. Glass beads exhibiting a high refractive index of 3 to 2.7;
A synthetic resin molded product characterized by containing 0.5 to 30% by weight of crosslinked polystyrene beads, crosslinked acrylic beads, etc., singly or in combination. (2) The synthetic resin molding according to claim 1, which is a variety of containers for cosmetics, medicines, etc. molded by injection molding, blow molding, extrusion molding, cast polymerization molding, etc., or various shapes for various other uses. thing.