JPS6228737B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for continuously producing a laminate of thermoplastic foam with an integrated reinforcing scrim.

More particularly, the present invention relates to an improved method for continuously manufacturing thermoplastic foam laminates without undesirable bowing or bowing.

By passing thermoplastic foams through a heated blade between them to thermoplasticize adjacent surfaces.
Lamination is often desired. Adjacent surfaces are then crimped together, fusing both surfaces together to create a laminate of the desired size. In many processing methods, it is desirable to incorporate a coarse fabric, such as a glass fiber cloth, into such a laminate for reinforcement. Such laminates are used for cryogenic vessels (cryogenic vessels) based on the so-called spiral generation technique (a method in which a band-shaped insulating material is spirally wrapped around a three-dimensional surface such as an LNG tank to form an insulating layer). Can be used to insulate containers containing low-temperature substances such as LNG.
Such techniques are disclosed in US Pat. No. 4,017,346 and US Pat. No. 4,050,607. Furthermore, U.S. Patent No.
No. 4,049,852 describes a laminate manufacturing apparatus suitable for the spiral generation method, and US Pat. No. 3,919,034
No. 3,924,039 and No. 3,954,539 describe various forms of laminates suitable for the spiral generation method. Often, this type of laminate exhibits some curvature along the longitudinal axis after it is prepared. The reason for the occurrence of such undesired curvature is unknown, and since it often occurs in an undesired direction, it is mentioned in the art regarding billets or bars that it can be adapted to the desired shape. As such, excessive mechanical treatments had to be applied to the lamination. In the case of thermal insulation of cryogenic vessels, in order to minimize the possibility of cracking of the insulation laminate due to thermal stresses,
There is a need to prevent mechanically induced undesired tensile stresses in the insulation.

Next, the method of the present invention will be explained in more detail with reference to the drawings.

1 and 2, a laminate manufacturing apparatus 10 is schematically illustrated including an operatively associated frame and support device (not shown). A supply roll 11 is supported on the frame for dispensing a reinforcing rough cloth 12. The reinforcing rough cloth 12 includes a first series of foam bodies 13 made of a synthetic resin material arranged end-to-end.
and a second series of foam bodies 14, also made of synthetic resin. That is, the rough cloth 12 is arranged between the adjacent surfaces of the foams 13 and 14. First pair of payroll rolls 15,1
6 is a second pair of feed rolls or pressure rolls 1;
8, 19, the foams 13, 14 and the rough cloth 12 are carried. Adjacent to the feed rolls 18, 19 and spaced apart from the feed rolls 15, 16, a blade heating device 2 is provided.
1 is placed. In order to prevent folds or creases from occurring in the rough cloth, a blade-shaped heating device 2 is used.
1 and the salary roll 11,
Advantageously, it is supported by a smooth metal plate (not shown). The blade-shaped heating device 21 includes a blade-shaped heating element 22 which passes through the middle of the foams 13, 14 to thermoplasticize and increase the temperature of the adjacent surfaces of the foams 13, 14. Raise the temperature to a temperature sufficient to cause disintegration. These foams 13 and 14 are
and a second pair of pull-out rolls 23, 24 and 25, 26 to remove it from the area of the blade heating device 21. By the above-mentioned pull-out roll pressing both heated surfaces of the foam,
A rough cloth is built into the thermally plasticized and broken down foam. The thermally plasticized material of the foam fuses with each other through the mesh or cavities created between the rough cloths, thereby embedding the rough cloths therein and forming a combined plastic material. I hope you understand that it is a layer of chemical substances. Upon cooling, the plasticized material is cured with a reinforcing rough cloth placed approximately in its center, permanently bonding the foam to each other.

The blade-shaped heating device 21 depicted in FIG.
It is equipped with The heating element 22 is provided with a large number of small holes in areas where the most heat is required to be generated, and is approximately square or rectangular in shape. The thickness of the heating stop is such that it is of sufficient strength during use and that the voltage applied to the plate carries enough current to heat the adjacent surfaces of the foam to a temperature sufficient to soften or melt the foam. It's not that important, other than letting it flow. In an advantageous embodiment, the heating element has a serpentine shape, as shown in FIG. Serpentine shaped heating elements are well known in the art. The heating element 22 includes a first
is conveyed into a frame or support member 32 and suitably insulated therefrom. This heating element 22
is fixed to the first support member 32 by a screw 33 insulated therefrom. A second support member 34, only the lower half of which is shown, is spaced apart from the first support member 32. The heating element 22 is made of glass fiber.
It is insulated from the second support member 34 by an insulating material 36, such as a siloxane resin laminate.

FIG. 4 shows a cross-sectional view of the heating element 22, in which the rough cloth 12a is threaded through a central, transversely arranged groove 37 of the element. Insert a rough cloth 12 into such a groove of the heating element.
By passing a, the frictional pull forces on the adjacent surfaces of the laminated foam are approximately equalized, significantly reducing the tendency of the resulting lamination to warp.

FIG. 5 depicts, in cross-section, an alternative heating device 40 suitable for carrying out the invention. The heating device 40 consists of a first electrically resistive heating device 41 and a similar heating element 42 spaced apart and facing parallel thereto. Advantageously, both heating elements preferably have a serpentine shape, as in the heating element of FIG.
However, it will be apparent to those skilled in the art that heating element shapes other than serpentine may be used as well. Therefore, a single element bent in the opposite direction, ie, U-shaped, may also be used satisfactorily in the practice of the present invention. The heating elements 41 and 42 are separated by a plurality of spacing pieces 43, both of which are shaped like flat disks. This spacing piece is located at the end or reverse bend of the heating element, and its location is approximately that of support member 3 in FIG.
2,34. Thus, the heating elements of FIG. 5 are essentially heating elements as depicted in FIGS. 3 and 4, but they are positioned in spaced relation to each other, This serves as a passage for the reinforcing rough cloth 12b passed between them. Such heating elements used to carry out the invention preferably have opposing parallel major front faces and have a diameter of 6.3 mm, preferably 1.6 mm.
It is allowed to have a thickness not greater than mm.

The heating element 22 of FIG. 3 preferably has a diameter of about 3.2
The heating element 40 of FIG. 5 is made of a stainless steel plate having a large number of small holes of mm thickness, and the heating element 40 of FIG.
Advantageously, it is made from a stainless steel plate having a number of small holes, each approximately 1.6 mm thick, separated by 1.6 mm. For a laminate of expanded polystyrene having a density of about 32 kg per cubic meter, the heating element is heated to a temperature of about 316° C., as indicated by a thermocouple manually positioned on its surface. . The above heating power source can be AC or welding power source.
Even DC is fine.

The method of the present invention can be used with any thermally weldable synthetic resin thermoplastic foam to provide a laminate with minimal distortion or curvature. Depending on its use, the reinforcing rough cloth can be wider, narrower, or equal in width to the front width of the foam to be laminated. The coarse cloth may be continuous, as shown in FIGS. 1 and 2, or it may consist of a number of pieces of cloth joined in the longitudinal direction in terms of weight. by transversely extending pressure-sensitive adhesive tape or other fastening means;
It is convenient to join short pieces of cloth at the ends of each section. When producing long laminates for use in installing thermal insulation by the so-called spiral generation method, the curvature of the laminate should be equal to or less than the curvature of the device to which it is installed. It is highly desirable to maintain the value at

The invention is particularly suitable for making thermoplastic foam laminates for use in the insulation of cryogenic containers. A typical laminate can be made from, for example, five sheets of foam board. That is,
One 50mm x 200mm board is attached in a stratified manner to four 50mm x 150mm boards stacked in four tiers, with one edge of each 50mm x 150mm board attached to the 50mm x 200mm board. The coarse mesh cloth was thermally sealed to one front side of the plate and the sealed inner surface of the 50 mm x 200 mm plate was sealed. A 200mm x 200mm x square laminate is made. In addition, from two 100mm x 200mm plates with a coarse cloth sandwiched between them and welded together face to face,
A simpler laminate can be made. When making laminates in this way, when two plates are laminated using a heated blade and the fabric is applied and embedded into the weld between the two plates, there is no curvature or curvature in the laminate made. A non-negligible problem arises in that distortion occurs. The present invention reduces or eliminates such undesirable curvature or distortion.

In its wide range of applications, it has been found that by passing a rough cloth through a flat heating device, the curvature or distortion of the laminate is significantly reduced. It is believed that the mechanism for reducing such curvature is essentially based on balancing the opposing frictional forces on the opposing surfaces of the foams being combined.

The coarse cloth is heated by a flat heating element 22.
or a pair of flat heating elements 41, 4
2, the frictional forces on the laminated foams become equal. Bonding between the foams is accomplished by heating adjacent surfaces of the foams to plasticize, ie, soften or melt the substance, and then applying pressure to bring the two surfaces into contact. Heating the rough cloth itself has little effect on the degree of bonding between the foams. When the foam is pushed or pulled through the heating device and the foam to be laminated moves relative to the heated flat heating element, the foam contacts the fixed flat heating element. Friction occurs on the surface. When one flat heating element is used in the production of such a laminate, should the rough cloth to be incorporated into the weld line be inserted on one side of the heated flat heating element? Alternatively, there is a choice whether to insert it on the other side. Thus, one side of the flat heating element is in direct contact with the foam and the other side of the flat heating element is in direct contact with the rough cloth, so that both sides of the flat heating element are in direct contact with each other. Therefore, the frictional force will be different.

When the laminated rectangular foams are joined, as in the apparatus of FIGS. 1 and 2,
A heat seal or weld is applied over the entire contact surface of the foam. When the adjacent sides of the foam are heated to a temperature where they are bonded together, the rough cloth is embedded therein. If there are cavities, such as grooves or fillets, in the surface of the foam to be laminated, only a small portion of the rough cloth will be free to move.

[Brief explanation of the drawing]

Figure 1 is a side view of a laminate manufacturing apparatus using the present invention, Figure 2 is a plan view of the apparatus shown in Figure 1, and Figure 3 is a partially exploded view of the apparatus used in the first embodiment of the present invention. FIG. 4 is a cross-sectional view of the blade-shaped heating device of FIG. 3 showing the passage through which the reinforcing rough cloth is passed, and FIG. 5 is a plan view of the blade-shaped heating device according to the present invention. FIG. 3 is a cross-sectional view showing a pair of heating elements used in the embodiment of FIG. In the figure, 10: Laminate manufacturing device, 11: Feeding roll, 12: Rough cloth for reinforcement, 13: Synthetic resin material, 14: Foam, 15, 16: Feeding roll, 18, 19: Feeding roll, 21 : Blade-shaped heating device, 22: Heating element, 23, 24, 25, 26:
Drawer roll, 32: Support member, 33: Screw, 3
4: Support member, 37: Groove, 41, 42: Heating element, 43: Spacer piece.

Claims (1)

[Claims] 1. Heating adjacent surfaces of adjacent thermoplastic resin foams to a temperature sufficient to plasticize them; bringing the plasticized adjacent surfaces of the foams into contact; and A continuous manufacturing method for a laminate consisting of a foam and a reinforcing rough cloth, the method comprising the step of cooling the reinforced surface to form a joint that integrates a reinforcing rough cloth between the foams. , in order to reduce the degree of curvature of the laminate, the reinforcing rough cloth is passed through a flat heating element during heating of adjacent surfaces of adjacent foams, in order to reduce the degree of curvature of the laminate. A method for manufacturing a laminate consisting of a rough mesh cloth for reinforcement and a rough mesh cloth for reinforcement. 2. The method of claim 1, wherein the heating element is a generally flat sheet having a highly serpentine configuration. 3. The method of claim 2, wherein the rough cloth is threaded through approximately the center of the heating element. 4. The method according to claim 2, in which the rough cloth is arranged to
said method, being passed to the second side. 5. The method of claim 1, wherein the heating element comprises a pair of spaced flat blade-shaped members, and the rough cloth is threaded therebetween. 6. A method as claimed in claim 1, in which the heating element comprises a groove in a flat blade-shaped member and the rough cloth is passed through the groove;
The method comprises: a blade member bringing a first portion of the rough cloth into frictional contact with one surface of the blade member and a second portion of the rough cloth into frictional contact with an opposite surface of the blade member. . 7. A method as claimed in claim 6, wherein the groove is located approximately in the center of the flat blade member.