JPS6056535A - Equipment for producting thermoplastic resin foamed matter - Google Patents

Abstract

PURPOSE:To manufacture a foam having no wave and high quality continuously by successively passing an expansible thermoplastic resin sheet-shaped molding in a heating tank using a heating medium consisting of a low melting-point metal. CONSTITUTION:A thermoplastic resin sheet-shaped molding S having foamed capability fed from feed rolls 1 is introduced into a preheating tank 7, in which a liquefied heating medium N composed of a low melting-point metal, specific gravity thereof is larger than the molding S, is stored, through a guide roll 2. The molding is immersed in the heating medium N, and preheated to approximately 100-200 deg.C until it reaches to a foaming heating tank 8 side end in a belt conveyor 5. When the molding S passes through the foaming heating tank 9 side end in the belt conveyor 5, the molding floats on the surface of the heating medium N in the preheating tank 7 by the buoyancy of the heating medium N, and enters into a foaming heating tank 8. The molding S is heated by heat transfer from the heating medium N and thermal projection from a far infrared heater 20 from the surface side and foamed, thus manufacturing a foam Sa having predetermined density. The foam Sa is cooled by a cooling device 21 and cooling rolls 22, and wound as a product.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus for continuously producing thermoplastic resin foam.

Conventional equipment of this type includes a preheating zone for preheating a foamable thermoplastic sheet-shaped molded body using a liquid heat medium as needed, and a softening point tool for the preheated molded body. 2. The decomposition temperature of the foaming agent (1-2) includes a foaming zone in which the foam is heated by a heater.

However, in the conventional products of this kind, since the molded product is foamed while being supported by a bell conveyor in the foaming zone, there is a drawback that waves (waveforms) in 111 directions are not generated in the foamed product. Since oil is used as a heating medium, the deposited water must be washed and removed, but it is extremely difficult to completely remove it, and furthermore,
The disadvantage is that the entire device becomes large-scale.

The present invention was made in order to eliminate this conventional drawback, and uses a heated liquid of a low melting point metal as a heat medium, and immerses a thermoplastic resin sheet-like molded product with foaming ability in it. By creating a laminar flow of liquid, giving the laminar flow a divergent flow direction at a predetermined point, and causing this laminar flow to foam, a wave-free, high-quality product can be produced. The purpose of the present invention is to provide an economical apparatus for producing thermoplastic resin foams that can continuously produce foams, requires less heat, is smaller in scale than conventional equipment, and is economical.

Hereinafter, one embodiment of the present invention will be explained with reference to the drawings. A thermoplastic 4J (oil sheet-like molded body S) having foaming ability is placed on a guide roll 2.
It is fed to the heating tank 3 through the. The heating tank 3 is a tank with openings on two sides, and stores a liquid heat medium N made of a low melting point metal having a higher specific gravity than the molded body S.
It has a built-in heater 4 for heating to a temperature of . As this low melting point metal, for example, an alloy of lead and tin or lead and tin is used. Reference numeral 5 denotes a helt conveyor, which is arranged at an angle with its tip side immersed in the heat medium N in the heating tank 3 and its end side exposed outside the heating tank 3.
The molded body S sent through the guide roll 2 is transferred to the heating tank 3.
and immersed in the heat medium N for a predetermined period of time. The molded body S is uniformly heated by the heat medium N, and when it passes through the conveyor 5, it floats due to the difference in specific gravity with the heat medium N and becomes a foam Sa having a desired density. Note that 6 is an i-shield ring pump for heat medium N.

FIG. 2 and FIG. 3 show an embodiment of the second invention, in which a thermoplastic resin sheet 1 having a foaming ability 1 to a molded body S fed from a supply roll 1 passes through a guide roll 2 to a preheating tank ( or pre-crosslinking tank) 7. The preheating tank 7 is a tank with an opening on the top surface, and stores a liquid heat medium N made of a low melting point metal having a higher specific gravity than the compact S, and is equipped with a heater 4 for heating this heat medium N to a temperature of 100 to 200''C. ... is built in. As this low melting point metal, for example, an alloy of lead and tin or an alloy of lead and tin mixed with bismuth, sintered, etc. is used. 5 is Bell 1 - A conveyor, which is arranged at an angle with the leading end immersed in the heat medium N in the preheating tank 7 and the rear end coming out of the preheating tank 7, and has supply rolls ■,
The molded body S sent through the guide roll 2 is transferred to the heating tank 3.
into the heat medium N inside, and immersed in the heat medium for a predetermined time.
Preheat after heating! The foaming heating tank 8 connected to Ft 7 is sent. The molded body S is uniformly heated by the heat medium N, and when it passes through the conhes 1 and 5, it becomes rp due to the difference in specific gravity with the heat medium N.
J. Add foam! : The laminar flow of heat medium N, which will be described later, created by tank 3 moves. The foaming heating tank 8 is an inclined tank in which the heat medium N overflows from the preheating tank 7 and has a plurality of heaters 9 built therein. This heater 1]
is foaming addition p', +5 heating medium N in tank 8 from 100 to 25
(Heat to a temperature of 1'C. The foaming heating tank 8 has a row of heat medium supply holes II at predetermined intervals in the diagonal direction and a row of plates 13 on the flow direction side. The supply hole row II is made up of a plurality of supply holes 10 arranged in a neutral force 1iJ line, and the flow direction control weir plate row 13 is a plurality of weirs that give the flow direction of the heat medium N in a letter-shaped flow direction toward the downstream. It consists of a plate 12.The heating medium supply nozzle 14 injects and supplies the heating medium N sent from the preheating tank 7 through the supply pipe 16 and the regulating valve 17 by the pump 15 onto the end of the preheating tank 7.10 is an overflow receiver. The overflow portion of the heat medium N flowing down into the downstream end 1 shell of the foaming heating tank 8 is received, and this ohaf r-1- portion is recovered into the preheating tank 7 through the recovery pipe 19. 2o... - Far-infrared heaters are arranged on both sides of the foaming heating tank 8 at a predetermined interval in the flow direction of the heat medium N. Reference numeral 21 is an air float type cooling device, which The sent-out foam Sa is cooled and sent out on the cooling roll 22 side.

As described above, the molded body S is first guided into the preheating tank 7, where it is immersed in the heating medium N, and then heated through the bell 1-combate 5.
100-200℃ by the time it reaches the side edge of the foaming heating tank 8.
The temperature is set in advance. The molded body S is conveyed by belt conveyor 5
When it passes through the side end of the foaming heating tank 8, it floats on the surface of the heating medium N in the preheating tank 7 due to the buoyancy of the heating medium N and enters the foaming heating tank 8. Since the molded product S has a ratio smaller than the specific gravity of the heat medium N as shown in the figure, the molded product entered into the foaming heating tank 8 has a lower specific gravity than the heat medium N in the foaming heating tank 8. Laminar flow-1-
8 and move from the back side during the movement? jA degree 1
Due to heat transfer from the heat medium N at 00 to 250°C, and from the far infrared heater 20 from the surface side! A4 is heated to a temperature equal to or higher than the decomposition temperature of the softening agent-3 foaming agent to form a foam Sa having a predetermined density. Foam S
a is a cooling device 21, cooling 1. After being cooled by the trolley 22, it is wound up as a product.

In the present embodiment shown in FIGS. 2 and 3, the laminar flow of the heat medium N flows down by the weir plate 12 while being directed toward both end forces, and the formed body S on the laminar flow is caused to flow in a wide direction. Therefore, the molded body S foams without producing waves.

In addition, the molded body S was placed in a liquid heat medium (((flow),
Since ζ foams, the molded body S is uniformly heated and foams uniformly.

In addition, since the heat medium is a low melting point metal, it does not adhere to the molded body N, so that it is possible to prevent L+'/lj from occurring in the heat medium, and the heat transfer rate J is also good.

Note that the heald conveyor 5 of this embodiment is not limited to this, but may be any one that has the function of guiding the molded bodies S into the heat medium N of the preheating tank 7.

As described above, according to the present invention, the thermoplastic resin sheet I-shaped molded body is heated uniformly and with good heat transfer efficiency by the heating liquid of the low-melting point metal as the heating medium flowing into the heating tank, thereby producing a high-quality foam. can do.

Further, according to the second invention, in the foaming heating tank, a laminar flow of a liquid heat medium of a low-melting point metal having a specific gravity larger than that of the molded body is formed, and a flow direction is given to the laminar flow so that it diverges toward the downstream. By adopting a configuration in which the molded body is supported and foamed by this laminar flow, the molded body is foamed while receiving an extremely light force directed toward both ends of the molded body, so that a high-quality foamed body without waves can be manufactured. Can be done. In addition, since the heat medium is a low melting point metal, the heat transfer efficiency is high, and since the above liquid heat medium is used as the heat medium in the preheating tank instead of conventional oil, there is no need to clean the foam. Since the scale of the equipment can be made smaller than before, there is a good chance that energy costs and installation costs can be greatly reduced.

[Brief explanation of drawings]

11th example, 1) 1st example of the present invention
Top view, Figure 2 4.1 Example 14 of other embodiments
The figure is a plan view of an embodiment not shown in FIG. 2. 3-heating tank, 4.9-heater, 5-＼ru1~ln・＼
Ya, 7-preheating tank, 8-shot? Ii /Jl+ #:! +
1”/, 11-heat medium supply hole row, 13 flow direction control column 4 row, 14-heat medium supply nozzle, N11k-shaped heat medium, S molded body, Sa foam/patented 1 Sekisui Chemical Co., Ltd. r', Industry Stock J4 (Meeting 11 Representative Motoshi Fujinuma

Claims (1)

[Claims] 1. In an apparatus in which a thermoplastic resin sheet I-shaped molded body having a foaming ability is continuously passed through a heating tank to be heated and foamed, a low melting point metal is used as a heat medium passing through the heating tank. 4! Use a heated liquid of 4! An IM packing apparatus 2 for thermoplastic resin foam having a foaming property, a preheating tank for immersing and preheating a thermoplastic resin sheet-like molded body having foaming ability in a liquid heat medium, and supporting the preheated molded body with a support means. The thermal iiJ plastic resin foam is equipped with a foaming heating tank that heats and foams the foam.
In the A-forming apparatus, the support means for the molded article No. 11 in the foaming heating tank is an IN flow of a liquid heat medium, and the flow direction is widened toward the flow at one or more predetermined points of the laminar flow. 1. An apparatus for producing a thermoplastic resin foam, characterized in that the liquid heat medium of the preheating tank (1) and the foaming heating (4FF) is a low melting point metal having a higher specific gravity than the molded body.