JPH0762367B2 - Method for manufacturing heat insulating sheet having dew condensation preventing surface - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a cross-linked polyolefin resin foam sheet for use in roofing materials, ceiling materials, etc., which is laminated on a metal folded plate or the like and has a surface thereof. The present invention relates to a method for manufacturing a heat insulating sheet having a dew condensation preventing function.

[Conventional technology]

Conventionally, a crosslinked polyolefin resin foam sheet is used as a heat insulating material for a metal folded plate because it has closed cell properties, excellent heat insulating properties, and high flexibility.

By the way, this crosslinked polyolefin resin foam sheet has no water absorption and has a smooth surface, so that when it is directly stuck to a folding plate, it cannot hold water vapor or condensed water on its surface, and water drops drop indoors. There is a problem such as.

Therefore, in Japanese Utility Model Application Laid-Open No. 45-32151, a laminated sheet for preventing dew condensation is obtained by heat-sealing a laminated body of a fiber web and a foam sheet, which are integrated by needle punching on a closed-cell type foam sheet. Is proposed.

Further, in Japanese Utility Model Laid-Open No. 48-73923, a galvanized iron plate and a closed-cell expanded polyethylene resin plate are bonded together, but an open-cell expanded polyethylene resin plate is bonded to the outer surface of the closed-cell expanded polyethylene resin plate. Plank shingles have been proposed.

[Problems to be solved by the invention]

Each of the above-mentioned ones has a laminated structure using another water-retaining material on the outside of the closed-cell type foam sheet,
Both are complicated to manufacture and expensive.

An object of the present invention is to manufacture a heat insulating sheet having a dew condensation preventing surface simply and inexpensively without separately laminating a water retaining material.

[Means for solving problems]

The method for producing a heat insulating sheet having a dew condensation preventing surface of the present invention is characterized by continuously and mechanically tearing a crosslinked polyolefin resin foam sheet and forming raised irregularities on the tear surface.

In the present invention, the olefin resin used for the crosslinked olefin resin foam sheet is a polymer of olefin monomer such as low density polyethylene, medium density polyethylene, high density polyethylene, polypropylene, ethylene-propylene copolymer, ethylene. -Vinyl acetate copolymers, ethylene-vinyl chloride copolymers, ethylene-ethyl acrylate copolymer-based olefin-based copolymers, propylene-ethylene-1-butene copolymers, etc. Examples thereof include a terpolymer mainly composed of an olefinic monomer, a modified polyolefin such as chlorinated polyethylene, and the like, and a mixture of these polymers.

Then, the cross-linked polyethylene resin foam sheet, for example, a foaming agent is blended with the above-mentioned olefin resin, a temperature at which the foaming agent is not substantially decomposed by an extruder or the like, is kneaded and melted at a pressure to form a sheet, The sheet-shaped molded article is crosslinked by irradiating it with ionizing radiation and then heated to a temperature not lower than the decomposition temperature of the foaming agent to foam, or the resin mixture is blended with a foaming agent and a crosslinking agent, and the mixture is extruded by an extruder or the like. Examples include a method of obtaining a closed-cell crosslinked foam by kneading and melting at a temperature and pressure at which the foaming agent is not substantially decomposed, forming into a sheet shape, crosslinking, and further activating above the decomposition temperature of the foaming agent.

In the foamable resin composition, polymerizable monomers, heat stabilizers, antioxidants, extenders, plasticizers, flame retardants, colorants, antistatic agents, fillers, etc., as long as they do not interfere with crosslinking or foaming. Can be added.

When ionizing radiation is used as a means for crosslinking the resin, β-rays, γ-rays, neutrons, electron beams, etc. are used, and the irradiation dose is in the range of 1 to 20 Mrad in terms of surface absorbed dose. Adjust this irradiation dose to 50%
If the degree of cross-linking is lowered as follows, the bubbles in that part will be larger than in other parts, and not only will it be easy to tear to a nearly uniform thickness, but the raised density of the tear surface will be high, and a product with excellent water retention will be obtained. It is preferable because it is possible.

In this invention, the crosslinked resin foam sheet is mechanically torn continuously to form raised irregularities on the tear surface, but the tear portion is the thickness of the crosslinked resin foam sheet. Nearly the center of the method, both torn and available as a product are preferred.

[Action]

The method of the present invention, as described above, by continuously mechanically tearing the crosslinked olefin resin foam sheet,
The bubble wall in that portion is pulled and cut into a nap-like shape, and nap-like irregularities are easily formed.

Therefore, the raised irregularities exert a function of retaining water vapor and condensed water.

〔Example〕

 Hereinafter, the method of the present invention will be described with reference to the drawings.

FIG. 1 schematically shows the method of the present invention, in which 1 is a cross-linked polyethylene sheet having a thickness of about 8 mm which is not yet cut, and the central portion of which has an electron irradiation dose of about half that of the surface portion. Since the amount was changed, the degree of cross-linking was lowered and the bubbles were enlarged.

The crosslinked foamed sheet 1 is mechanically torn continuously from the left side in FIG. Then, the foamed sheet 1 is peeled off from the central portion having large air bubbles so that the upper and lower portions have substantially the same thickness, and the raised surface unevenness 111 is formed on the tear surface. Then, as shown in FIG. 2, a heat insulating sheet 11 having raised irregularities 111 on one surface is obtained.

This heat insulating sheet 11 is attached to a folded plate with the raised irregularities 111 on the outside to form a heat folded plate.

〔The invention's effect〕

In the method for producing a heat insulating sheet having a dew condensation preventing surface of the present invention, a crosslinked polyolefin resin foam sheet is continuously and mechanically torn to form a raised unevenness having a water retaining function on the tear surface. Therefore, it is possible to easily and inexpensively manufacture a heat insulating sheet having a dew condensation preventing surface without separately providing a water retaining material such as an open cell foam sheet or a fibrous sheet on the surface of the crosslinked polyolefin resin foam sheet.

[Brief description of drawings]

FIG. 1 is a vertical sectional view schematically showing the method of the present invention, and FIG. 2 is a sectional view of a heat insulating sheet having a dew condensation preventing surface manufactured by the method of the present invention. 1 ... Crosslinked polyolefin resin foam sheet 11 ... Heat insulation sheet, 111 ... Brushed unevenness

Claims (2)

[Claims] 1. A method for producing a heat insulating sheet having a dew condensation preventing surface, which comprises mechanically continuously tearing a crosslinked polyolefin resin foam sheet and forming raised irregularities on the tear surface. 2. A crosslinked polyolefin resin foam sheet,
The method for producing a heat insulating sheet having a dew condensation preventing surface according to claim 1, wherein the tear portion has a degree of crosslinking smaller than that of the other portions.