JPS61248727A - Sheet or film of uniform multi-axially orientated thermoplastic resin - Google Patents

Abstract

PURPOSE:To permit to form the uniform thin multi-axially orientated sheet by compression forming by a method wherein the sheet or the film of thermoplastic resin, having specified draw ration per unit area as well as thickness and small in a difference between the maximum polarized fluorescent component strength IMAX and the minimum polarized fluorescent component strength IMIN, is employed as the material of the sheet or the film. CONSTITUTION:The orientated sheet of the orientated film of thermoplastic resin, having 2X or more of draw ration per unit area and the thickness of 1mm or less while the difference between the maximum polarized fluorescent component strength IMAX and the minimum polarized fluorescent component strength thereof is in the relation of IMAX-IMIN/IMAX<0.1, is employed for the compression forming. Here, the polarized fluorescent component strength means the same strength in all angular direction, which is measured by a polarized fluorescent light photometer when the axes of deflection of two sheets of polarizing plates, which are put before and after the sheet or the film, are arranged in parallel. The draw ratio per unit area of the sheet should be 2X or more and is preferable to be 3X or more and 20X or less. When it is 2X or more, the effect of orientation is realized generally and when it is 2X or more, the effect is realized well while the forming of uniform multi-axial orientation becomes difficult generally when it is more than 20X. The thickness of the sheet should be 1mm or less and is preferable to be 10Xm-0.5mm.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a uniformly multiaxially oriented thermoplastic resin sheet or film (hereinafter referred to as "sheet aluminum or film").
(abbreviated as “sheet”), which has optical properties, thermal properties,
It has uniform mechanical properties and can be used favorably in precision electronic equipment parts.

[Conventional technology and problems]

Thermoplastic resin for precision electronic equipment parts, light electrical equipment parts, etc.
Axially oriented sheets are widely used. For example, biaxially oriented sheets of polyethylene terephthalate (hereinafter abbreviated as PET) are widely used in floppy disks and the like. Precision products such as floppy disks are strictly required to have dimensional stability, and it is preferable that dimensional changes due to temperature be isotropic. Conventionally, biaxially oriented sheets such as PET have been used for these purposes, but uniform multiaxially oriented sheets are preferable.
That is what is required. Many technologies have been introduced so far for forming biaxially oriented sheets, and they are also used industrially, but there are no good forming methods for multiaxially oriented sheets, especially thin uniform multiaxially oriented sheets. It has not been.

A method of molding an oriented thermoplastic resin article by compression molding is disclosed in USP 3,632,841 and the like.

That is, it has been shown that the inner surface of a compression goo is coated with a lubricant, and a thick thermoplastic resin base is compressed in a compression die at a temperature above the glass transition temperature and below the melting point to achieve biaxial orientation.

In this compression molding method, the required compression force varies depending on the thickness of the resin base, and as the base becomes thinner, a higher compression force is required. Therefore, conventionally, it has been virtually impossible to mold a thin multiaxially oriented sheet using this compression molding method, and a uniform thin multiaxially oriented sheet has not been produced.

[Means and effects for solving the problem] As a result of research on multiaxially oriented molding technology, the present inventor found that sheets formed by multiaxially oriented compression molding are extremely uniformly multiaxially oriented. This led to the present invention. That is, the present invention is an oriented sheet or film of thermoplastic resin, which (a) has an area ratio stretching ratio of 2 times or more, and (b)
The thickness is 1 m or less, and (c) fluorescence polarization component intensity in all angular directions measured with a polarization fluorophotometer (fluorescence when the polarization axes of two polarizing plates placed before and after the sheet or film are parallel); This is a uniformly multiaxially oriented thermoplastic resin sheet or film characterized by the difference between the maximum weight (MAX) of the light polarization component intensity (light polarization component intensity) and the thickness (M□N).

The thermoplastic resin mentioned in the present invention is generally a thermoplastic resin that can be compression molded, such as polystyrene, styrene, etc.
Acrylonitrile copolymer, ABS resin, polyvinyl chloride, polymethyl methacrylate, polycarbonate), P
Polyesters such as ET, nylons such as nylon 6, nylon 66, and nylon 46, polyolefins such as polyphenylene ether, polyetherimide, polyoxymethylene, polyethylene, and polypropylene, various fluororesins, and blends and copolymers of these resins. Such as merging.

Acrylic resins based on methyl methacrylate (hereinafter abbreviated as MMA) can be used satisfactorily, including polymethyl methacrylate (hereinafter abbreviated as PMMA), MMA and alkyl acrylate copolymer (C!O (MMA-AA)), MM.
A-Maleic anhydride-styrene terpolymer ((:!
o(MMA-MAJ(-8t)), MMA-methacrylamide copolymer (Co(MMA-MAAmid)
e)), etc. can be used successfully. Also, polyester such as PET, polybutylene terephthalate, nylon 6
, nylon 66, nylon 46. Nylon 12 etc. can also be used successfully.

Various fillers such as short fibers such as glass fibers, carbon fibers, asbestos, and synthetic fibers, long fibers of synthetic fibers with high elongation, mica, etc. can be blended with the resin described in the present invention.

Carbon fiber, polyamide resin, polyester resin, etc.
A sheet blended with Kepler fibers (aromatic polyamide) and the like and uniformly multiaxially oriented with a high degree of orientation becomes a homogeneous sheet with a high Young's modulus.

The area ratio stretching ratio of the sheet of the present invention is 2 times or more, preferably 3 times or more and 20 times or less. At 2 times or more, a stretching effect generally appears, at 3 times or more, the effect appears well, and at 20 times or more, uniform multiaxial orientation generally makes molding difficult. Preferred sheets of the present invention are highly polyaxially oriented sheets, with average orientation release stress (hereinafter OR
8) is preferably subjected to multiaxial orientation of 10 kg/crIL2 or more, more preferably 15 kg
/c! It is 1L2 or more. 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 D 15041C.

The thickness of the sheet of the present invention is 1 mm or less, preferably 10 mm or less.
It is 0.5u from μm. The present invention includes not only flat sheets but also curved sheets.

The sheet of the present invention is a uniformly multiaxially oriented sheet, and the uniformity of the multiaxial orientation was measured using a polarized fluorophotometer. For a method to measure molecular orientation with a polarized fluorometer, see J.P.
oly, Sci., c-15, 237 (1966)
.

Jasco Report, Dan, 116 (196
9).

This is a method of determining the state of fluorescent molecule orientation from the angular distribution of the polarization characteristics of the fluorescent light emitted by the fluorescent molecules fixed in the sheet.

An important feature of this method is that it takes advantage of the double optical anisotropy exhibited by fluorescent molecules when absorbing light and when emitting fluorescent light. The molecular orientation that has been described, including the type of orientation, is directly measured as an orientation pattern that indicates the state of orientation. The measurement method is Ja
sco Report・i・116 (1969)
The equipment consists of the following:

The fluorescence polarization component intensity I when the polarization axes of two polarizing plates (PtsPs) placed before and after the light source sheet are parallel is measured by rotating the sheet (sample) 360 degrees, and the maximum IMAX in all angular directions is measured. The smaller the difference between the minimum IMIN and the minimum IMIN, the more uniform the multiaxial orientation is.
MAX-IM Engineering)/"MAX is 0.1 or less, preferably 0.05 or less, more preferably 0.02 or less, and is a uniformly multiaxially oriented sheet. Fluorescent polarization component intensity I is When shown in a circular pattern, the angles with a difference of 180° are in principle equal to each other, 'max and ■.

,. The ratio can also be found by comparing the diameters of the circular patterns. The value of "MAX'EEN)/"MAX of the present invention was also determined by measuring the diameter of the circular pattern.

As a result of studying methods for molding thin sheets with uniform multiaxial orientation, we discovered that compression molding is preferable, and further developed a compression molding technique that can satisfactorily mold the sheets of the present invention. A compression molding method that can successfully mold the sheet of the present invention will be described below.

In the method of compressing a thermoplastic resin base material in a compression die to form an oriented molded product, 1. Two or more layers of thermoplastic resin base materials are placed one on top of the other in a non-adhered state in the die; 2. The interface between the inner surface of the die and the surface of the resin base is brought into a lubricated state; 3. The resin base is compressed at a temperature above the glass transition temperature and below the melting point of the resin base to orient the resin base; 4) After cooling, the resin base is taken out from inside the die and each base is This is a compression molding method for multiaxially oriented molded products, which is characterized in that two or more molded products are obtained by peeling the oriented molded products that have been molded from each other.

Laying two or more layers of thermoplastic resin substrates in a non-adhered state as described here means that after stacking and compression molding, the oriented molded products formed from each substrate can be easily separated from each other. It is to leave it in a non-adhesive state.

A method in which a resin base and a non-adhesive resin film or sheet are placed at the interface of each base can be used particularly well. In this case, the non-adhesive resin film or sheet preferably has a viscosity close to that of the resin base during molding, and particularly preferably has a viscosity in the range of 1/30 to 30 times. When the viscosity difference between the resin base and the non-adhesive resin film or sheet is small °C, when the resin base is stretched during compression molding,
The adhesive resin film or sheet is also stably stretched, resulting in a uniformly oriented molded product. The most preferable non-adhesive resin film or sheet is one that has a viscosity of 1 to 20 times the viscosity of the resin base upon molding and has a smooth surface. When a film or sheet having a higher viscosity than the resin base and a smooth surface is used, the surface of the film or sheet is transferred to the surface of the molded product, resulting in a molded product with a smooth surface.

If the thermoplastic resin substrates are non-adhesive to each other at temperatures below their melting point, the substrates are piled up as they are and compression molded, and after molding, each layer is peeled off to obtain an oriented molded product.

Polytetrafluoroethylene and the like can be well molded by this method.

In order to make the interface between the inner surface of the die and the surface of the resin substrate lubricated, apply a lubricant to the inner surface of the die, or provide a sheet containing a lubricant at the interface between the inner surface of the die and the substrate. It can be kept in a lubricated state.

Orientation by compression at a temperature above the glass transition temperature and below the melting point of the resin base material can be achieved by uniformly plug-flowing the stacked base materials within the die due to compressive force. Uniform plug flow molding is possible by keeping the interface between the die inner surface and the resin base surface well lubricated.

Although the stretching ratio can be selected as necessary, it is preferably 2 to 20 times in terms of area ratio.

[Explanation with drawings]

The present invention will be explained with reference to the drawings.

FIG. 1 shows the process of forming a multiaxially oriented sheet by compression molding.

FIG. 2 shows the relationship between the thickness of the multiaxially oriented sheet and the required compression force when Co(MMA-AA) is made into a multiaxially oriented sheet by the method shown in FIG.

FIG. 3 shows the process of molding a multiaxially oriented sheet by compression molding.

FIG. 4 shows various methods of placing four layers of resin substrates on top of each other in a non-adhered state.

In Fig. 1, a lubricant is applied to the inner surface 2 of the compression die 1, a plate-shaped base material 3 of thermoplastic resin is placed (1-1), and the temperature is lower than the glass transition temperature and below the melting point of the base material 3. After heating, the substrate 3 is compressed to cause plug flow and multiaxial orientation (1-2
) and then cooled as is to obtain a multiaxially oriented sheet 4. The compressive force required to mold the multiaxially oriented sheet 4 depends on the type of resin,
It varies depending on the stretching temperature, stretching ratio, thickness of the multiaxially oriented sheet, etc.

Figure 2 shows how methyl acrylate 5 was prepared by the method shown in Figure 1.
This figure shows the relationship between the thickness of a multiaxially oriented sheet and the necessary compressive force when Co(MMA-AA)' of % by weight is stretched to 5 times the area ratio at 140°C. As the thickness of the multiaxially oriented sheet becomes thinner, a higher compressive force is required, making it difficult to stably perform plug flow molding. Furthermore, the manufacturing cost of a compression molding device increases in proportion to the compression force, and therefore, the thinner the sheet, the higher the molding cost.

Therefore, it is difficult to mold a uniformly oriented sheet having a thickness of 1 fi or less using the compression molding method shown in FIG.

FIG. 3 illustrates a method for successfully forming the sheet of the present invention. After applying a lubricant to the inner surface 6 of the compression die 5, a non-adhesive film 8 was placed on each interface and both surfaces of the four thermoplastic resin substrates 7, and placed in the compression die.
(3-1). After heating the substrate 7 to a temperature above the glass transition temperature and below the melting point, the substrate 7 is compressed and caused to plug flow to form four multiaxially oriented sheets 3-2), and then cooled as it is to form four multiaxially oriented sheets 9. Take out the axially oriented sheet 9 from the compression die 5 (3-3), then peel off each multiaxially oriented sheet and further peel off the non-adhesive film from the oriented sheet to obtain a thin multiaxially oriented sheet 10 ( 3-4).

FIG. 4 shows various methods of placing two or more layers of thermoplastic resin substrates on top of each other in a non-adhesive manner. (4-1
) is a method in which the resin substrates 11 are stacked as they are, or a method in which a lubricant or mold release agent is applied to each interface 12 of the resin substrate 11, and (4-2) is a method in which each interface and surface of the resin substrate 11 is non-adhesive. Method of placing resin film 13, (4-3)
A non-adhesive resin film 13 is placed on each interface of the resin base 11, and the entire stacked base is covered with a non-adhesive resin film 14.
(4-4) is a method in which two types of non-adhesive resins 15 and 16 are alternately layered, and (4-5) is a method in which the resin base is a three-layered material consisting of a surface layer 17 and an inner core 18. This shows the case of molding a three-layer multiaxially oriented sheet,
This is a method in which two three-layer resin bases are stacked and a non-adhesive film 19 is placed on the interface and both surfaces. (4-6) is a stack of two or more resin substrates with different thicknesses, in which a thick substrate 20 and a thin substrate 21 are placed one on top of the other, and a non-adhesive resin film or sheet 22 is placed on each interface. It is something that The resin substrate may be thinner than the non-adhesive resin sheet placed on its interface, and (4-7) is an example in which a thin resin substrate 23 is sandwiched between thick non-adhesive resin sheets 24.

The method (4-7) can be used particularly well when forming a thin oriented sheet of 100 μm or less. Among these various methods, method (4-3) can be used most favorably.

That is, by vacuum packaging the resin base material, it is possible to prevent air from remaining at the overlapped interface and deteriorating the surface of the molded product. Using a resin base with a mirror-like smooth surface,
By using a non-adhesive resin film or sheet with a mirror-like smooth surface, vacuum packaging as shown in (4-3), compression molding and biaxial orientation, a biaxially oriented molded product with a smooth surface can be obtained. This is the most preferred example of the present invention.

The method shown in (4-2), in which two or more resin substrates are placed and a non-adhesive film is placed on each substrate interface and both surfaces, can also be used successfully.

The film or sheet for vacuum packaging may be the same as or different from the film or sheet placed on each resin substrate interface. For stable plug flow compression molding, it is preferable to use a sheet on the outermost surface that has good slippage with the inner surface of the die.

[Effects of the present invention]

As a result of developing a compression molding method suitable for forming thin sheets with uniform multiaxial orientation, we were able to obtain uniform multiaxially oriented sheets that were previously impossible to obtain.

Uniform multiaxially oriented sheets have uniform optical properties, thermal properties, and mechanical properties, and can be well used in precision electronic equipment parts such as floppy disks, or audio equipment such as drum skins.

〔Example〕

Next, the present invention will be explained with reference to Examples.

Example 1 Methyl acrylate 5% by weight Co (MMA-AA
) and 0.02% by weight of stilbenemethylbenzoxazole (Whitex RP manufactured by Kyodo Kagaku Co., Ltd.) as a fluorescent agent. A 100 μm thick non-oriented mirror-finish polypropylene sheet was placed on the interface of the polypropylene sheet, and the 10-layer thick base was vacuum-packed with the polypropylene sheet to provide a base for compression multiaxial orientation molding. As shown in Fig. 3, polydimethylsiloxane is applied to the inner surface of the compression die, and the compression die and resin base are heated to 140°C and compressed to form a plug 70-, resulting in multiaxial orientation with an area i ratio of 4 times. did.

After cooling the compression die and cooling the multiaxially oriented molded product, the molded products are taken out from the compression die, each molded product is peeled off from each other, and the polypropylene is further peeled off, resulting in a smooth surface of 0.5 m.
Ten m-thick PMMA multiaxially oriented sheets were obtained.

The uniform multiaxial orientation of the polypropylene film molded at the same time as the PMMA multiaxially oriented sheet having a thickness of 0.5 mm was measured using a polarizing fluorescence photometer model FOM-2 manufactured by JASCO Corporation. In addition, the ORB and various physical properties of the PMMA sheet were measured and are shown in the following table. The sheet exhibited remarkable uniform multiaxial orientation.

In addition, a 25 μm thick multiaxially oriented polypropylene film that was molded at the same time was impregnated with a fluorescent agent and measured (IMAX
"N)/MAX" was 0.05, which also showed uniform multiaxial orientation.

Example 2 Molding was carried out in the same manner as in Example 1 using the following resins and films at the following molding temperatures.

For each resin, 10 0.5 mm thick multiaxially oriented sheets with smooth surfaces and 10 25-mm multiaxially oriented films were obtained in one molding process. The (IMAX-I, Engineering N)/'MAX value of these multiaxially oriented sheets and films is 0.0
It was in the range of 2 to 0.09, and was uniformly multiaxially oriented.

[Brief explanation of the drawing]

Figure 1 is a schematic explanatory diagram showing the process of forming a multiaxially oriented sheet by compression molding, and Figure 2 is a multiaxially oriented sheet obtained when Co (MMA-AA) is made into a multiaxially oriented sheet by the method shown in Figure 1. A graph showing the relationship between thickness and required compressive force. Fig. 3 is a schematic explanatory diagram showing the process of forming a multiaxially oriented sheet by compression molding. Fig. 4 is a graph showing the process of forming a multiaxially oriented sheet by compression molding. Fig. 4 is a graph showing the process of forming a multiaxially oriented sheet by compression molding. It is a schematic sectional view showing various methods of stacking.

Claims (2)

[Claims] (1) It is an oriented sheet or film of thermoplastic resin, (a) the area ratio stretching ratio is 2 times or more, (b) the thickness is 1 mm or less, and (c) it is measured with a polarized fluorophotometer. Fluorescent polarized component intensity I in all angular directions (fluorescent polarized component intensity when the polarizing axes of two polarizing plates placed before and after the sheet or film are parallel)
The difference between the maximum I_M_A_X and the minimum I_M_I_N is (I_M_A_X - I_M_I_N)/(I_M_A_
X) A uniformly multiaxially oriented thermoplastic resin sheet or film, characterized in that <0.1. (2) A sheet or film according to claim 1 formed by compression molding.