JPH07156322A - Plastic sheetlike object and method for production thereof - Google Patents

Abstract

PURPOSE:To obtain a sheetlike object having composition distribution continuously in the thickness direction by a method wherein the sheetlike object is composed of at least two different kinds of resin components and the resin composition is changed obliquely in the thickness direction CONSTITUTION:Resin components A and B are both melted and fed to quantitative gear pumps 5 and 6 having the ports on the discharge side branched into a number of flow passages 11 and 12. The amounts of the resin components A and B flowing into the flow passages 11 and 12 are appropriately regulated by flow controllers 13 and 14 directly connected to the quantitative gear pumps 5 and 6 taking into consideration the composition in the thickness direction after the mixing. The number of the branched flow passages 11 and 12 is determined according to the degree of the composition distribution of the intended sheetlike object. The resin are collected from the flow passages 11 on the side of the resin component A and the corresponding flow passages 12 on the side of the resin component B. The resins are stirred and mixed by a mixing nozzle 15 in each of the flow passages where they meet one another. The molten resins mixed uniformly and different in the mixing ratio in each flow passage are sent into a multilayer extrusion die 7 and are extruded therefrom.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plastic sheet material in which the resin composition gradually changes in the thickness direction and a method for producing the same.

[0002]

2. Description of the Related Art Conventionally, a large number of plastic sheet-like materials provided with various functions using a plurality of resins have been manufactured. To obtain such a sheet-like material, generally, a method of blending different resins and melt-extruding, or a method of laminating several layers of different resins is adopted.

[0003]

However, although the melt-extrusion method is an economical method, only plastic sheet-like materials having a constant composition in the thickness direction can be obtained. On the other hand, the sheet-like material obtained by the laminating method has different components and physical properties in the thickness direction, and there are cases where the use of both sides of the sheet is restricted from the viewpoint of design.

In recent years, it has been desired to develop a plastic sheet-like material having a composition different in the thickness direction, that is, physical properties gradually changing in the thickness direction depending on the intended use. The current situation is that no has been obtained.
Therefore, the present inventors have found that a plastic sheet-like material having a composition changed in the thickness direction can be obtained by adopting a specific molding method for a plurality of resins, and completed the present invention. It was

[0005]

The present invention comprises at least two aspects.
There is provided a plastic sheet-like article, which is composed of different kinds of resin components and in which the resin composition changes in a gradient in the thickness direction.

The plastic sheet material of the present invention (hereinafter,
Abbreviated as a sheet. ) Is composed of at least two different resin components. Any resin can be used as the resin component as long as it can be melt-extruded, and the combination of resins can be arbitrarily selected according to the physical properties to be imparted to the sheet-shaped material. For example, a combination of poly (methyl methacrylate) and poly (vinylidene fluoride) or the like can be adopted as long as it is a sheet-like material which is transparent as a whole and in which the refractive index changes in an inclined manner. Further, each resin component may be a mixture of different resins.

The resin components constituting the sheet-like material do not have to be different resins, but may be a combination of resins of the same type, the composition of which is changed by the addition of additives or the like. For example, when polymethylmethacrylate alone is combined with polymethylmethacrylate mixed with inorganic particles such as calcium carbonate or magnesium sulfate, a sheet-like material having a light diffusion property varying in the thickness direction can be obtained. In addition to these, examples of additives include antistatic agents, impact modifiers, ultraviolet absorbers, antioxidants, antibacterial agents, dyes, pigments and reinforcing agents.

The sheet material of the present invention is (1) a plurality of resins are melted and supplied to a multi-discharging type metering gear pump, and (2) each molten resin is distributed into a large number of flow paths and flow rates. (3) By collecting the flow paths of different resins and changing the composition of the resin stepwise, (4) mixing and stirring for each of the collected flow paths, and (5) discharging and stacking them from a multilayer die. It can be manufactured.

Hereinafter, the method for producing a sheet-like material of the present invention will be described with reference to the drawings, taking as an example the case where the number of resins used is 2 (denoted as A component and B component). 1 and 2
Shows a schematic view of an apparatus for producing the sheet material of the present invention, FIG. 1 is a view seen from the top, and FIG. 2 is a view seen from the side. FIG. 3 is a diagram of the branching of the flow path by the constant volume gear pump, and the mixing and stirring section. It should be noted that when the number of resins is 3 or more, the device is the same as the illustrated device.

First, (1), each of the resin A component and the resin B component is melted and supplied to the multi-discharge type constant gear pumps 5, 6. Specifically, the component A is supplied from the hopper 1 and the component B is supplied from the hopper 2, melted and extruded by the extruders 3 and 4, respectively, and then supplied to the constant amount gear pumps 5 and 6.

Next, (2), each of the melted resin components A and B is divided into a large number of flow paths and flow rates, different resins are collected, and the resin composition is changed stepwise. More specifically, the discharge side ports of the metering gear pumps 5 and 6 are branched into a large number of flow paths 11 and 12, as shown in FIG. The number of branches of the flow channels 11 and 12 is manipulated depending on the degree of composition distribution of the target sheet-like material, but about 10 is sufficient. The flow rate of the A component or the B component to each of the flow paths 11 and 12 is set in consideration of the composition after mixing.
Flow controllers 13 and 14 directly connected to the gear pump
Is properly controlled by.

Next, (3), the resin of the flow path 11 on the A component side and the corresponding resin of the flow path 12 on the B component side are collected. The stepwise change of the composition is determined according to the composition change of the sheet material to be produced.

FIG. 4 and FIG. 5 are views showing examples in which the composition changes of the component A and the component B are made in the thickness direction of the sheet-like material to be manufactured. FIG. 4 shows a composition in which the composition of the component B is maximized on the surface of the sheet, that is, the m surface and the n surface, and the composition is gradually changed such that the component A is maximized at the center of the thickness. The composition is changed such that the amount of the A component gradually increases from the m surface to the n surface, that is, the amount of the B component decreases. These composition changes can be freely set by changing the discharge side flow rates of the metering pumps 5 and 6.

Next, (4), mixing and stirring are performed for each of the assembled flow paths. Specifically, the respective mixing channels as shown in FIG. 3 are stirred and mixed in the mixing nozzle 15. This operation is performed by a static stirrer 16 having a twist structure, which is inserted into the mixing nozzle 15.

Subsequently (5), they are discharged from the multilayer die 7 and laminated. Specifically, the molten resins in the respective channels, which are uniformly mixed and have different mixing ratios, are sent to the multilayer extrusion die 7 and discharged so that the required composition distribution is obtained. The shape of the extrusion die 7 is determined by the resin used, the shape of the sheet material to be manufactured, and the like.

FIG. 6 shows a flow rate adjusting nozzle. As shown in FIG. 6, the flow channels 11 and 12 are respectively connected to the flow rate adjusting nozzle 1
The number of layers to be laminated can be increased by further branching by 7 and 18. Flow rate adjusting nozzles 17, 1
8, the flow rate of each flow path can be adjusted by, for example, the diameter and length of the nozzle. The number of branches is 1 for each flow path
It is about 0, and the number of stacked layers can be up to about 10 × 10 = 100. The composition distribution can be made smoother by increasing the number of layers.

[0017]

【Example】

[Example 1] Polymethylmethacrylate (P
MMA), polyvinylidene fluoride (PVD) as B component
F) was used, and the melting discharge temperature of PMMA and PVDF were both set to 155 ° C. The number of flow path branches of each gear pump is 10, and the mixed composition of PMMA and PVDF in the collected flow paths is PMMA / PVDF = 9.5 / 0.5, 9 /
1, 8.5 / 1.5, 8/2, 7.5 / 2.5, 7 /
3, 6.5 / 3.5, 6/4, 5.5 / 4.5, 5 /
It was changed stepwise to 5. Diameter 10 mm, length 100
mm by a static stirrer, and the mixture was discharged from a multi-layer die consisting of 10 layers and laminated to obtain a sheet-like material having a thickness of 6 mm and a width of 50 mm. The composition distribution of the obtained sheet-like product is shown in FIG.
It was shown to. The composition distribution was obtained by measuring the refractive index distribution.

[Example 2] Polymethylmethacrylate (PMMA) was used as the component A, and polymethylmethacrylate (pigment-containing PMMA) containing 0.3% of the dye Sumiplast Blue GP was used as the component B. Both components were used. It was melted at 220 ° C., and the number of flow path branches of each gear pump was set to 10. The mixed composition of the PMMA and the dye-containing PMMA in the assembled channel is PMMA / dye-containing PMMA = 10/0, 9 /
1, 8/2, 7/3, 6/4, 5/5, 4/6, 3 /
It was gradually changed to 7, 2/8 and 1/9. Diameter 10
mm, mixing with a static stirrer with a length of 100 mm,
Discharge from a multi-layer die consisting of 10 layers, stack, and thickness 6m
A sheet-like material having an m and a width of 50 mm was obtained. The colorimetric density distribution of the obtained sheet-shaped product is shown in FIG. The colorimetric density is
It was determined by measurement with a reflection colorimetric densitometer.

[0019]

INDUSTRIAL APPLICABILITY The present invention is a sheet material having a composition distribution continuously in the thickness direction. According to the present invention, various resins can be used, the thickness and composition distribution of the sheet material. It has many advantages such as easy operation.

[Brief description of drawings]

FIG. 1 is a top view of a sheet-shaped product manufacturing apparatus.

FIG. 2 is a side view of an apparatus for manufacturing a sheet material.

[Fig. 3] Flow path branching and mixing by a constant-volume gear pump,
It is a figure of a stirring part.

[Fig. 4]

FIG. 5 is a composition distribution diagram in the thickness direction of a sheet-shaped material.

FIG. 6 is a diagram of a flow rate adjusting nozzle.

FIG. 7 is an explanatory diagram of composition distribution in the thickness direction of the sheet in Example 1.

FIG. 8 is an explanatory diagram of a colorimetric density distribution in the thickness direction of the sheet in Example 2.

[Explanation of symbols]

 1, 2 hopper 3,4 Extruder 5,6 Gear pump 7 Multi-layer die 11,12 Branch flow path 13,14 Flow controller 15 Mixing nozzle 16 Static agitator 17,18 Flow adjustment nozzle

[Procedure amendment]

[Submission date] March 7, 1994

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] Brief description of the drawing

[Correction method] Change

[Correction content]

[Brief description of drawings]

FIG. 1 is a top view of a sheet-shaped product manufacturing apparatus.

FIG. 2 is a side view of an apparatus for manufacturing a sheet material.

[Fig. 3] Flow path branching and mixing by a constant-volume gear pump,
It is a figure of a stirring part.

FIG. 4 is a composition distribution diagram in the thickness direction of a sheet-shaped material.

FIG. 5 is a composition distribution diagram in the thickness direction of a sheet-shaped material.

FIG. 6 is a diagram of a flow rate adjusting nozzle.

FIG. 7 is an explanatory diagram of composition distribution in the thickness direction of the sheet in Example 1.

FIG. 8 is an explanatory diagram of a colorimetric density distribution in the thickness direction of the sheet in Example 2.

[Explanation of Codes] 1, 2 Hopper 3,4 Extruder 5,6 Gear Pump 7 Multilayer Die 11,12 Branching Flow Path 13,14 Flow Controller 15 Mixing Nozzle 16 Static Stirrer 17,18 Flow Control Nozzle

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location B29C 47/92 9349-4F // B29L 7:00

Claims (3)

[Claims] 1. A plastic sheet material comprising at least two different resin components and having a resin composition that changes in a gradient in the thickness direction. 2. (1) A plurality of resins are respectively melted and supplied to a multi-discharge type metering gear pump, (2) each molten resin is distributed to a number of flow paths and flow rates, and (3) different resins The flow path is assembled to change the composition of the resin stepwise, (4) each of the assembled flow paths is mixed and stirred, and (5) they are discharged and laminated from a multi-layer die. Manufacturing method of the plastic sheet material. 3. The method for producing a plastic sheet-like article according to claim 2, wherein the flow path branched by each gear pump is further provided with a flow rate adjusting nozzle to increase the number of branches so that the composition change is made smoother.