JPS61132343A - Multilayer sheet-shaped molded shape - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention is a novel multilayer sheet-like molded product that is prevented from adhering to dust. The multilayer sheet-like molded product of the present invention is a synthetic resin sheet having durable dust adhesion prevention properties, and can be favorably used as a glazing material.

[Conventional technology]

As hard synthetic resin sheets, sheets made of acrylic resin, polycarbonate, etc. have been widely used so far. Acrylic sheets have transparency, weather resistance, hardness, bending rigidity,
Excellent tensile strength, polycarbonate sheet is heat resistant,
They have excellent flame retardancy and are widely used. One of the drawbacks of these sheets is that they tend to be charged with static electricity, and as a result, they tend to attract dust, become dirty, and have a reduced transparency.

Generally, to prevent static electricity on synthetic resin sheets, an antistatic agent such as a surfactant is kneaded into the synthetic resin, and the antistatic agent bleeds out onto the sheet surface, which improves the conductivity of the sheet surface. Use the effect to ℃・ru. However, the glass transition temperature of acrylic resins and polycarbonate resins is much higher than the usage temperature, so even if an antistatic agent is mixed in, the amount of antistatic agent that bleeds to the surface is very small. Kneading the agent has little effect.
A method of applying an antistatic agent to the surface of the sheet is also used, but since the applied layer has poor abrasion resistance, it easily loses its performance due to friction, etc., and is also easily exposed to water, etc. It peels off and cannot withstand long-term use. Durable antistatic properties are required.

[Problem that the invention seeks to solve]

The present invention has been made in view of the above points.

That is, an object of the present invention is to provide a multilayer sheet-like molded product that can maintain antistatic performance over a long period of time without deterioration of antistatic performance due to bleeding of antistatic agent or friction. [Means and effects for achieving this] The present invention provides a multilayer sheet-like molded product in which the image surface layer is composed of a hard synthetic resin layer, and the conductive layer in contact with the soft synthetic resin layer is present within one inch from the surface of the molded product. It is.

Since the conductive layer of the molded product of the present invention is located on the inner layer of the molded product, the conductive layer is not easily damaged by external forces (in addition, it does not come into direct contact with moisture, chemicals, temperatures, or other various solvents). As a result, it has excellent water resistance, chemical resistance, and solvent resistance, and by using a material that reflects or absorbs ultraviolet rays on the surface layer, it has the characteristic of becoming a molded product with extremely excellent weather resistance. The molded product of the present invention has a conductive layer in the inner layer, and since the conductive layer is located near the surface within 1 mx from the sheet surface, 1- Static air, r) Yui, 72 As most of the electric lines of force are directed toward the conductive inner layer, the external electric field becomes significantly smaller, resulting in antistatic effect similar to that of molded products with a charged layer on the surface. It prevents the adhesion of dust due to static electricity, and is effective in shielding static electricity from the outside.

In the present invention, the term "dust adhesion prevention" refers to the purpose of reducing the external electric field due to static electricity even if the product is charged, and means preventing dirt.

The hard synthetic resin referred to in the present invention is a transparent synthetic resin that is generally used as a glazing material, and is a rigid, high °C hard resin with a glass transition temperature higher than room temperature, such as acrylic resin, polycarbonate a resin, polystyrene. , styrene-acrylonitrile copolymer, hard polyvinyl chloride resin, etc. Acrylic resins and aromatic polycarbonate resins are particularly preferred for the present invention. As the acrylic resin, polymers mainly composed of methyl methacrylate (hereinafter referred to as "P") can be used well, and polymethyl methacrylate (hereinafter referred to as P
MMA), copolymer of MMA and alkyl acrylate (hereinafter abbreviated as Cio (MMA-AA)), MMA
and an unsaturated carboxylic acid, or a copolymer of an unsaturated carboxylic acid anhydride, MMA and an unsaturated carboxylic acid, or an unsaturated carboxylic anhydride, and optionally a copolymer of Copolymers containing methyl styrene, α-methyl styrene, acrylonitrile, methacrylate, alkyl acrylate, etc. have good weather resistance, transparency, hardness, bending strength, etc., and can be used well. As the alkyl acrylate to be polymerized, methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, etc. can be favorably used.For unsaturated carboxylic acids and unsaturated carboxylic acid anhydrides to be copolymerized with MMA, Acrylic acid, methacrylic acid, itaconic acid, fumaric acid, maleic acid, maleic anhydride, itaconic anhydride, etc. can be used. Furthermore, polymethyl α-chloroacrylate, etc. can also be used.

Aromatic polycarbonate containing bisphenol A can be used favorably as the polycarbonate resin.

Various additives can be added to these synthetic resins as necessary. For example, heat stability, ultraviolet absorbers, heat ray absorbers, colorants, glass fibers, various fillers, etc. are added as necessary.

In addition to the above properties, the biaxially oriented sheet of acrylic resin also has impact resistance, and is therefore very suitable as a glazing material, and can be particularly well used as the glazing material of the present invention. The biaxially oriented sheet has an average orientation release stress (hereinafter abbreviated as OR8) of 15 kg/'Cm2.
It is preferable that the above biaxial orientation is applied.

OR8 indicates the degree of orientation of the sheet and is the shrinkage force when the sheet is heated.

The OR8 measurement method is a method based on ASTM D1504, and details are shown in Japanese Patent Application No. 57-52283.

In the sheet of the present invention, the average QR, S is 15 kgZα2 or more,
More preferably 20 to 40 kg/cm, a strong 2
Particularly preferred are sheets that are axially oriented. Biaxial orientation of the acrylic resin sheet increases its impact resistance, and when the OR8 is 15 kg/'cm2 or more, the impact resistance becomes significantly higher. The relationship between OR8 and impact strength is shown in Japanese Patent Application No. 57-52283.

The biaxial orientation described here refers to uniform orientation in two axial directions, and includes slight differences in OR8 and stretching ratio in the two axial directions.

The soft synthetic resin described in the present invention is a soft synthetic resin as opposed to a hard synthetic resin, and is a resin having a small bending elastic modulus, a small hardness, and a large tensile elongation. Preferably, A.S.
The bending elastic modulus measured according to the measurement method according to TM D790 is 3/4 or less, more preferably 3/4 of that of hard synthetic resin.
~1/4. It is preferable that the soft synthetic resin has adhesive properties with the hard synthetic resin with which it is combined, and for example, the combinations of resins shown in the following table can be used satisfactorily.

Furthermore, in the combinations shown in the following table and other combinations, an adhesive layer may be provided at the interface between the hard synthetic resin layer and the soft synthetic resin layer, if necessary. Such an adhesive layer exhibits adhesive strength to two layers that have poor adhesion to each other.

In the present invention, many resins used in the adhesive layer are classified as soft synthetic resins, and can be used alone as soft synthetic resins.

As shown in the table, particularly preferred soft synthetic resins are those that have improved impact resistance and/or are made softer than hard synthetic resins. Rubber reinforced PMMA
, rubber-reinforced Co (M1'1iA-AA), rubber-reinforced polystyrene, AES [The resin is a resin in which a rubber component is introduced into the corresponding hard synthetic resin mainly by graft polymerization and/or polymer grating to improve impact resistance. However, it has a multiphase structure with a resin component as a continuous phase and a rubber component as a dispersed phase, and is currently being industrialized and used in large numbers on clothing. In addition, when transparency is required in the molded product of the present invention, the refractive index of the rubber component and the refractive index of the resin layer may be adjusted to be almost the same, and/or the particle size of the dispersed rubber component may be adjusted to be less than the wavelength of visible light. It is possible to use a soft synthetic resin that has been made transparent by, for example, adjusting it to

In addition, soft polyvinyl chloride is made of hard polyvinyl chloride with low-molecular plasticizers such as dioctyl phthalate and rubber.
It is softened by blending polymeric plasticizers such as rubber kraft copolymers. The rubber content and the amount of plasticizer/polymer plasticizer etc. in these rubber reinforced resins should be such that the flexural modulus of the soft synthetic resin is 374 or less of the flexural modulus of the combined hard synthetic resin, preferably 1. For <, an amount of 3/4 to 1/4 is required. Needless to say, the combination of hard synthetic resin and soft synthetic resin in the molded article of the present invention is not limited to those listed in the table above. The thickness of the soft synthetic resin layer may be thin, and is generally appropriately selected from 1 μm to less than 1 μm, preferably from 10 μm to 100 μm.

The conductive layer described in the present invention has a surface resistivity of 101
It is 2Ω or less, preferably 10,100 or less, more preferably 1,080 or less.

It is a thin layer having conductivity, such as a thin layer of an antistatic agent, or a fat-breakable layer kneaded with an antistatic agent. Various surfactants can be used effectively as the antistatic agent, and when water is absorbed, the conductivity increases and an antistatic effect appears.

Various surfactants can be used as the antistatic agent that can be used in the present invention, and any of anionic, cationic, nonionic, and amphoteric surfactants can be used. For example, quaternary ammonium salts, carboxylic acid metal salts, sulfonic acid metal salts,
Polyoxyethylene compounds etc. can be used. It is also effective to apply a water-absorbed antistatic agent or to use a water-absorbed resin.

Use an antistatic agent that becomes conductive when it absorbs water (・
In this case, the use of an acrylic resin mainly consisting of a canopy with high water absorption properties will particularly increase the antistatic effect, which is preferable in the present invention.

In addition, the conductive layer described in the present invention is processed to have a conductive fine powder such as a fine powder whose main component is a metal such as tin oxide, and to reduce the particle size to 01 μm or less in order to impart special transparency. It is also possible to use the conductive fine powder layered with a binder material at a temperature of 0.degree. C., or a resin layer kneaded with the conductive fine powder.

Furthermore, in order to improve the conductivity of various surfactants, etc., it is preferable to add the conductive fine powder to the field diagram active agent, etc.
0 A thin conductive layer is sufficient, generally 1 of the sheet thickness.
/10 or less, preferably 0.1μ77L to 11n1X,
More preferably, the thickness is 1 μm to 100 μm. The conductive layer needs to have adhesive properties with the synthetic resin layer.

The adhesion described here means that the multilayer sheet has enough adhesive strength to withstand general usage, and generally does not peel easily when measuring the falling weight impact strength of the sheet. means that the force is O,s kg or more,
Preferably, 1 kg or more can be used satisfactorily.

It is most preferable that the conductive layer has sufficient adhesive strength with the synthetic resin. However, if the adhesive strength is insufficient, a very thin adhesive layer or adhesive layer may be present at the interface between the conductive layer and the synthetic resin layer. can. Further, an appropriate amount of adhesive or adhesive can be added to the conductive agent. In this case, the surface resistance of the conductive layer increases as the amount of the adhesive increases, so the amount of the adhesive should be adjusted so that the surface resistance of the conductive layer is 1012 or less. Must be decided - 0 Conductive agent and adhesive to be used The appropriate blending amount of the adhesive will vary depending on the type of adhesive, but generally it is 80% by weight or less, preferably 50% by weight or less, and Preferably it is 25% by weight or less.

However, in the present invention it is preferred to use the antistatic agent alone. Antistatic agents generally have a small effect as an adhesive, but if a thin layer of antistatic agent is present at the interface of two synthetic resin layers and the agent is compressed and deformed at high temperature and high pressure, the two synthetic resin layers can be bonded together. Power increases.

It is necessary that the conductive layer be present within 100 degrees from the sheet surface. The closer the conductive layer is to the sheet surface, the greater the antistatic effect will be. Preferably, the surface of the sheet is between 0.01 and 0.01.
5 mm, more preferably in the range of 0.03 mm to 0.4 mm.

The larger the conductive dust in the antistatic layer is, and the closer the antistatic layer is to the surface, the greater the effect of directing the electric lines of force generated from static electricity on the sheet surface toward the inner layer. When the conductive layer is separated from the surface by more than IB, the dust adhesion prevention effect becomes smaller.

The sheet-like molded product of the present invention is a flat or curved sheet-like molded product, preferably 0.05 or more, 1
The sheet is 5 mm or less. In the present invention, the term "sheet" refers to plates, sheets, and films. When the sheet becomes thicker, it is preferable to have a total of two conductive layers within 1 mu from the front and back surfaces of the sheet. In the sheet-like molded product of the present invention, both the conductive layer and the soft resin layer are thin layers, and the total of the hard fat-retaining layers preferably accounts for half or more of the sheet, and more preferably 2 or more layers.

In the present invention, a conductive layer in contact with a soft synthetic resin layer exists inside the sheet. The presence of the conductive layer in contact with the soft synthetic resin layer makes it difficult to peel off when deforming forces such as bending or impact are applied to the sheet, resulting in an excellent sheet. It is thought that the soft synthetic resin layer acts as a buffer material when deformation force is applied to the sheet, making it difficult for the conductive layer to separate. The conductive layer is preferably sandwiched between soft synthetic resin layers, and by being sandwiched between the soft synthetic resin layers, it becomes more difficult to peel off and a good sheet can be obtained.

The sheet of the present invention can be molded using various methods.For example, it can be used with good compression moldability.

[Explanation with drawings]

FIG. 1 shows a cross section of a multilayer sheet-like molded product of the present invention.

FIG. 2 shows a method of molding the molded article of the present invention by compression molding.

In Figure 1, (1-1) is a hard synthetic surface fat layer 1 on the image surface layer.
, a conductive layer 3 sandwiched between soft synthetic resin layers 2 is present in the inner layer.

(1-2) has a hard synthetic resin layer 1 on the image surface layer, and a soft synthetic resin layer 2 and a conductive layer 3 on the inner layer.

(1-3) is a case of a thick sheet, in which two conductive layers 3 sandwiched between soft synthetic resin layers 2 are present near the surface.

(1-4) is a thick sheet in which there is one conductive layer 3 sandwiched between soft synthetic resin layers 2, and the effect of preventing dust from adhering to the surface on which the conductive layer 3 is present is obtained.

In (1-5), there are two conductive layers 3 in contact with the soft synthetic resin layer 2.

From (1-1) to (1-5), each layer is adhered to each other, and the conductive layer 3 is present within i rnx from the surface, preferably within 0.5 IN. In order to maintain the properties of the hard synthetic resin, especially its elastic modulus and surface hardness, it is preferable that the total of the hard synthetic resin layers is at least half the thickness of the entire molded product.
Furthermore, it is preferably 273 or more.

Further, in the molded product of the present invention, the conductive layer 3 is sandwiched between the soft synthetic resin layers 2 (1-1), (1-3), (
1-4) are particularly preferred. Since the properties of a hard synthetic resin are exhibited, the molded product of the present invention has a high modulus of elasticity.

Therefore, a large force acts on the conductive layer and its interface when subjected to deformation force or special impact force.

At this time, it is better to have the conductive layer 3 sandwiched between the soft synthetic resin layers 2 as shown in (1-1), (]-3), and (1-4).
2), it can withstand larger deformation force than cases like (1-5).

In FIG. 2, two hard synthetic resin bases 4 and two soft synthetic resin bases 5 are prepared, and a conductive material is applied to the inner surface 6 of the soft synthetic resin bases 5 (2-1).

Layer each substrate in the arrangement shown in (2-1) 2-2),
The laminate 7 is compressed using a compression mold 8 whose inner surface 9 is coated with a lubricant at a temperature above the glass transition temperature of each resin and below the melting point temperature of the hard synthetic resin ((2-3)→( 2-4) )
, biaxially oriented and stabilized in the compression mold 8 to obtain the molded article 10 of the present invention. 1 as hard synthetic resin base 4
It is possible to use a sheet with a thickness of 10 μm to 0°5 Hm as the soft synthetic resin base 5. The laminated resin base 7 is preferably vacuum-packed as a whole and then compression molded.

Here, "stabilize" means that when the molded product is taken out after biaxially oriented molding, the molded product will undergo large dimensional changes and/or
For example, if the base of the hard synthetic resin is an amorphous resin, the molded product is placed in a compression mold after biaxially oriented molding. If the hard synthetic resin is a crystalline resin, after biaxially oriented molding, the molded product is cooled at an arbitrary cooling rate in a compression mold to below the glass transition temperature or softening temperature. Cooling to an arbitrary temperature below the melting point (for example, in a room), or promoting crystallization at a relatively high temperature (for example, above the softening temperature and below the melting point) in a compression mold, or cooling and solidifying after that.

〔Example〕

The present invention will be explained below using Examples, but the present invention is not limited thereto.

Example 1 As a base material for a hard synthetic resin, cell-cast polymerization was used, and PMMA with a thickness of 2 mm and 15 beads was used as a plastic material (Praglas) with a flexural modulus of 35,000 ψ, etc. (2).
Use ℃・ta. A copolymer of methyl methacrylate and methyl acrylate (MA) (MF
R26, ASTM D-1238 (230'C, 3,8
kg)) of acrylic rubber was compounded. cO(MMA-M
A) Composition (flexural modulus 1 s o Ookg/cI
A 50 μm thick film made of rt2) was used. i
An antistatic agent based on an organic polymer that is commercially available as a t-agent (Colcoat) NR, 121X (manufactured by Colcoat Co., Ltd.) and an adhesive that is also commercially available as an acrylic polymer as a main component (Acrylic) T , A311(
A composition (solid content ratio 1.1) manufactured by Taisei Kako Co., Ltd. was used.

A solution of a conductive agent was applied to one side of a soft synthetic resin substrate, and after drying, a conductive layer of about 10 Am was formed.

The surface resistance value of the conductive layer is 1.5X], 08Ω (23°C
It was 150RJ (conditioned diameter measured).

The soft synthetic resin substrates on which the conductive layers are formed are stacked so that the conductive layers are in contact with each other, and this and the hard synthetic resin substrate are stacked according to the arrangement shown in Figure 1 (1-3). The carcasses were made into FBI-stacked carcasses with a thickness of about 20 mm. This was vacuum packed in a bag made of a 100 μm sheet made of polypropylene.

After applying a lubricant mainly composed of polydimethylsiloxane to the surface of a mirror-like compression mold and heating it to 150°C, the vacuum-packed thick-walled laminate preheated to about 150°C was placed in the compression molding mold. It was sandwiched and compressed to achieve biaxial orientation. Peel and remove the outermost polypropylene sheet to a thickness of approximately 4 mm.
An axially oriented multilayer sheet-like molded article (A) of the present invention was obtained.

In the molded article, one conductive layer is placed on each of the front and back sides at positions approximately 0.4 mm from the surface. The properties of the molded article are shown in Table 1.

Example 2゜Using the hard synthetic resin substrate, soft synthetic resin substrate, and conductive agent used in Example 1, they were overlapped according to the arrangement shown in Figure 1 (1-5) to a thickness of approximately A thick laminate with a thickness of 2 mmryr was obtained. This was biaxially oriented by compression molding in the same manner as in Example 1 to obtain biaxially oriented multilayer sheet-like molded products (E) and (C) of the present invention having a thickness of about 4 mm. In the molded article, one conductive layer is disposed on each of the front and back sides at a position of about 0.4 feathers from the surface. The properties of the molded article are shown in Table 1.

Comparative Example 1゜The hard synthetic resin base and conductive agent used in Example 1 were used (・
Then, a conductive layer was formed by applying a conductive agent directly to the hard synthetic resin base. The conductive layer was placed approximately 0.4 mm from the surface, with one conductive layer on each side, and the thickness was approximately 4 rttt, except that a soft synthetic resin base was not used.
A multilayer sheet-like molded product with x biaxial orientation was obtained. The properties of the molded article are shown in Table 1.

Comparative Example 2 A cell-cast polymerized PMMA sheet (Asahi Kasei Corporation, Plugras ■K) with a thickness of 20 mm, which can be used as a base material for hard synthetic resin, was used in place of the thick laminate of Example 1. Then, it was molded by compression molding in the same manner as in Example 1 to obtain a biaxially oriented single-layer sheet-like molded product having a thickness of about 4 wings. The properties of the molded article are shown in Table 1.

Table 1 shows that the presence of the soft synthetic resin layer improves the falling weight impact strength of the multilayer sheet-like molded product of the present invention to the same level as that of a single layer, and that the conductive layer prevents dust from adhering. It can be seen that the performance is extremely good. It can also be seen that the optical properties and mechanical properties are equivalent to those of a single layer.

*1 Regarding the measurement of dust adhesion prevention performance ■Dust suction height ash test) measurement 15CrrLX
The surface of a 15 cm sheet was electrically charged by rubbing it 20 times with a cotton cloth, and when the friction surface was approached from above the cigarette ash, the distance at which the ash began to be attracted and adhered was measured.

■Measurement of surface chamber level The surface of a 15cm x 15cWL sheet is rubbed with a cotton cloth 30 times to charge it, and the surface potential is measured 30 seconds after the friction ends using a surface electrometer (STATIRON-M, manufactured by Shishido Shokai @). did.

For both (1) and (2), the test pieces were conditioned at 23°G and 50RJ, and measurements were also conducted at 23°C and 50RH.

〔Effect of the invention〕

This is a sheet-shaped molded product that economically achieves the prevention of dust adhesion due to static electricity on hard synthetic resins with a high glass transition temperature, which is difficult to prevent static electricity, by minimizing the performance deterioration of the hard synthetic resins. It can be well used for hard synthetic resin sheets such as glazing materials, signboards, various displays, instrument covers, etc.

[Brief explanation of the drawing]

FIG. 1 is a schematic sectional view showing a cross section of a multilayer sheet-like molded product of the present invention. FIG. 2 is an explanatory diagram showing a method of molding the molded article of the present invention by compression molding. 1... Hard synthetic resin layer 2... Soft synthetic resin layer 3... Conductive layer 4... Hard synthetic resin base 5... Soft synthetic resin base 6... Inner surface 7... Lamination Body 8... Compression mold 9... Inner surface 1o... Molded product

Claims (1)

[Claims] A multilayer sheet-like molded product in which both surface layers are made of hard synthetic resin layers, and the conductive layer in contact with the soft synthetic resin layer is present within 1 mm from the surface of the molded product to prevent dust from adhering.