JPH071549A - Thick synthetic resin plate extrusion mold - Google Patents

Abstract

(57) [Summary] [Purpose] A thick synthetic resin that is a normal rigid vinyl chloride resin and that enables the extrusion molding of good quality thick rigid vinyl chloride plates (20 mm or more) without using a particularly large extruder. Provided is a resin plate extrusion molding die. A synthetic resin plate extrusion molding die having a manifold 13, a choke bar, and upper and lower lips 2a, 2b in this order, and a resin passage portion 4 extending from the vicinity of the outlet of the manifold 13 toward a lip outlet 10. Are divided into upper and lower portions 4a and 4b by the plate-shaped core 3, and choke bars 5a and 5b are provided on both the upper side and the lower side of the plate-shaped core 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mold for extrusion molding a synthetic resin plate, which is useful for extruding a hard vinyl chloride plate having a thickness of 20 mm or more.

[0002]

2. Description of the Related Art In the production of synthetic resin sheets, the extrusion molding method is more continuous than the calendering method, the press working method, etc., and has excellent manufacturing efficiency and simplification of the working process. It has advantages such as obtaining
It has become the mainstream method of manufacturing gats.

In order to manufacture a synthetic resin sheet by this extrusion molding method, a sheet-shaped synthetic resin extruded from a sheet molding die is passed through a polishing roll to polish and polish. The sheet-like synthetic resin coming out of the roll is transferred by a traveling roll group, and during this transfer, it is cooled and solidified by natural cooling, and the sheet-like synthetic resin which has been cooled and solidified is collected by a roll. Taking over.

As the above-mentioned sheet molding die, a fishtail die, a T-type manifold die, and a coat hanger are used.
Although dies, circular dies, and screw dies are known, a coat hanger die is usually used for extrusion molding of a hard vinyl chloride sheet having a sheet thickness of about 7 mm to 15 mm. It is used.

FIG. 2 shows a conventional coat hanger die, in which the resin flowing in from the inlet 12 'is wide in the width direction (sheet) in the manifold 13' (which spreads in a fan shape around the resin inflow point).
It is spread in the direction of the toe width), passes directly below the choke bar 5 ', and is pushed out from the tip of the lip, and the choke bar 5'is adjusted up and down by an adjusting bolt to move the choke bar 5'from the manifold 13' The resin is circulated and flowed through the smooth without passing through the lip 5a 'and 2b' via the blade 5 '.

[0006]

However, when a hard vinyl chloride plate having a thickness of 20 mm or more is extruded by using the above coat hanger die, the volume of the resin flow passage in the mold becomes large. , It becomes difficult to smoothly sneak the resin, resin retention is likely to occur, and product quality deterioration is likely to occur due to thermal decomposition of the resin. It is inevitable to increase the cost of, and if the resin stagnation is prevented by increasing the resin flow rate,
It is necessary to increase the resin flow rate considerably, and there are disadvantages such as inevitably increasing the size of the extruder.
With a die, it is difficult to extrude a good quality thick-walled rigid vinyl chloride plate at low material cost and low equipment cost.

The object of the present invention is a conventional hard vinyl chloride resin, and a thick-walled synthetic resin capable of extrusion-molding a good-quality thick-walled hard vinyl chloride plate (20 mm or more) without using a particularly large extruder. An object is to provide a resin plate extrusion molding die.

[0008]

DISCLOSURE OF THE INVENTION A mold for extrusion molding a thick synthetic resin plate according to the present invention is a mold for extrusion molding a synthetic resin plate having a manifold, a choke bar and upper and lower lips in order. -The resin flow path portion from the vicinity of the outlet of the sleeve toward the lip outlet is divided into upper and lower parts by the plate-shaped core, and choke bars are provided on both the upper side and the lower side of the plate-shaped core. This is a characteristic configuration.

[0009]

The resin flow paths parallel to each other on the upper side and the lower side of the plate-shaped core are joined together before the lip outlet. The upper and lower parallel resin flow path portions up to this confluent point cause the resin to flow substantially the same, and the choke bar wraps the resin around and the flow of the resin to the lip becomes substantially the same. Done.

Therefore, in the case of a single resin flow path,
It is possible to extrude a resin having a thickness substantially twice that of the sheet under the flow and flow of a smooth resin corresponding to the extrusion molding of the sheet.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. 1A is a longitudinal cross-sectional explanatory view showing an embodiment of the present invention, and FIG. 1B is a cross-sectional view taken along line B-B in FIG.

1A and 1B, 1a is an upper mold and 1b is a lower mold, which is provided with a flange 11 connected to the barrel of the extruder, and has a resin inlet 12 and a manifold. It has a field 13. 2a is an upper lip attached to the tip side of the mold, and 2b is a lower lip. At least one of the two lips 2a and 2b can be finely adjusted in the vertical position by a vertical position adjusting bolt, but its structure is not shown.

Reference numeral 3 is a plate-shaped core that divides a resin flow path portion 4 extending from the vicinity of the outlet of the manifold 13 toward the lip outlet 10 into upper and lower portions 4a and 4b, and a front end 31 and a rear end 32 are isosceles. It has a triangular tip and is fixed to the inner surface of the mold at one or both ends.

The temperature of the plate-shaped core 3 can be adjusted by flowing the heating oil into the internal flow hole 33, heating the buried electric heater by energization, and the like. 5
Reference characters a and 5b are choke bars provided on the upper side and the lower side of the plate-shaped core 3, respectively.

In the above mold, choke bars 5a, 5
By adjusting b, the resin that does not stay in the manifold 13 wraps around, and the lip 2 passes through the choke bars 5a and 5b.
The flow of the resin without stagnation in a and 2b is guaranteed.

In this case, the resin from the manifold 13 is bisected into the upper side and the lower side of the plate-shaped core 3, and the flow of the resin in the respective shunts 4a and 4b is substantially the same. As the resin wraps around and the resin flows under the pressure, it joins before the lip tip, and if the thickness of the synthetic resin plate obtained by this joining is 2T, The respective resin flows in the lower flow paths 4a and 4b are
This can be substantially equivalent to the resin wraparound and the resin flow to the lip via the choke bar during extrusion molding of the sheet having the thickness T.

That is, in the mold shown in FIG. 1, by appropriately controlling the temperature of the plate-shaped core 3, the upper and lower resin flow paths 4a and 4b of the plate-shaped core 3 are separated from each other. Can be substantially equivalent to the resin flow path of a conventional mold having a single resin flow path having the same cross-sectional size.

Therefore, the width is 1000 mm and the thickness is 7 mm to 1
When a hard vinyl chloride sheet of about 5 mm is extruded using a conventional coat hanger die having a single resin flow path shown in FIG. 2, a flow path gap (c) of 2.0 before the choke bar is obtained. ~
The gap d just below the choke bar is 1.0 with respect to 4.0 mm.
If adjusted within a range of up to 3.5 mm, thermal decomposition due to resin retention can be eliminated and good quality can be guaranteed.

Therefore, according to the die of the present invention of the bisection parallel flow path system, in FIG. 1A, the flow path gap c before the choke bars 5a, 5b of the flow paths 4a, 4b is set to be two. .0 to
It is set to 4.0 mm, and the gap d immediately below the choke bars 5a and 5b.
The thickness is doubled (15 m
It is possible to extrude a good quality hard vinyl chloride sheet having a thickness of about m to 30 mm).

The tip angle θ of the plate-shaped core 3 becomes the confluence angle of the resin flows, which influences the interlaminar fracture strength of the confluent resin. Therefore, in order to ensure a sufficient interlaminar strength, 30 ^°
It is preferably set to 80 ^0.

By using the mold of the present invention, it is possible to extrude a hard vinyl chloride plate of good quality and thick. This is clear from the comparison between the following examples and comparative examples. Example In (a) of FIG. 1, the gap c before the choke bars 5a and 5b is 2.75 mm, the gap immediately below the choke bars 5a and 5b is 2.5 mm, and the gaps from the choke bars 5a and 5b are −
The distance from the lip 31 to the tip 31 of the core-shaped core is 180 mm, and the distance from the tip 31 of the plate-shaped core is 120 m from the lip outlet 10.
m, the upper and lower lip 2a, the gap between 2b to 30 mm, pre - set each tip angle of bets like core 3 theta to 45 ^0, extrusion flow rate under the mold mean temperature 180 ° C., a hard vinyl chloride resin It was extruded at 100 kg / hr.

Comparative Example In FIG. 2, the gap c in front of the choke bar 5'is 2.7.
5 mm, the gap d just under the choke bar 5'is 2.5 mm,
Set the distance from the lip tip 10 'to the choke bar 5'to 1
20mm, the gap between the upper and lower lips 2a ', 2b' is 30mm
, And the mold temperature and extrusion flow rate were the same as in the example.

When the outer skin of each extruded product was analyzed, carbonization of the resin was not observed in the example product, but carbonization was observed in 7 out of 10 samples in the comparative example product.

[0024]

The synthetic resin plate extrusion molding die of the present invention is
With the configuration as described above, even if the sheet to be molded has a large thickness and the volume of the resin flow path in the mold is large, the resin is prevented from staying well and good quality can be guaranteed.

Therefore, it is not necessary to increase the heat resistance of the resin used in order to prevent thermal decomposition due to the retention of the resin. In addition, the amount of resin extruded does not need to be high to prevent retention,
An extruder having a capacity adapted to the cross-sectional size of the product may be used.

Thus, by using the mold of the present invention, extrusion of a good quality thick synthetic resin plate, in particular, a hard vinyl chloride plate having a thickness of 20 mm or more at a normal material cost and a normal equipment cost. Molding becomes possible.

[Brief description of drawings]

FIG. 1A is an explanatory view showing an embodiment of the present invention,
1B is a cross-sectional view taken along the line of FIG.

FIG. 2 is an explanatory diagram showing a conventional example.

[Explanation of symbols]

 1a Upper mold 1b Lower mold 2a Upper lip 2b Lower lip 13 Manifold 3 Plate-shaped core 4 Resin flow passage portion 4a Upper flow passage of resin flow passage portion 4b Lower flow passage of resin flow passage portion 4 5a Upper side Choke bar 5b Lower choke bar

Claims (1)

[Claims] 1. A synthetic resin plate extrusion molding die having a manifold, a choke bar, and upper and lower lips in order, and a resin passage portion from the vicinity of the outlet of the manifold to the lip outlet is plate-shaped. It is divided into upper and lower parts by the core and cho
A mold for extrusion molding of a thick synthetic resin plate, characterized in that the knurling is provided on both the upper side and the lower side of the plate-shaped core.