JPH1142724A - Foam composite molded item with low heat conductivity - Google Patents

Abstract

PROBLEM TO BE SOLVED: To lower the heat conductivity of a molded item, and maintain the low heat conductivity for a long period of time by cutting and smashing used card or the like having a plastic orientation sheet as a base material, performing molding by filling the card pieces in foamable resin, and burying a metal body at the inside of the foam molded item. SOLUTION: The foam composite molded item A is manufactured such that card pieces 11 made by cutting and smashing used cards or the like having a plastic orientation sheet as a base material are filled in the foamable resin 12 for molding, a metal body 2 is buried in the foam molded item 1, and a cover later 3 is laminated at both the sides thereof. A filling quantity of the card pieces 11 is held in the range of 10/1-3/1 at a weight ratio of the card pieces/foamable resin. When an additive rate of the card pieces 11 is much more than 10/1, an integration of the card pieces 11 becomes insufficient resulting in the occurrence of separations and cracks, and when the card pieces 11 are less than 3/1, a mechanical strength of the foam composite molded item A is small in an improvement effect, so that a much filling rate is preferable in terms of recycling of the used cards.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a foamed composite molded article having a low thermal conductivity for use in electric refrigerators, freezers, refrigerated containers and the like for keeping heat and cooling.

[0002]

2. Description of the Related Art Insulation materials for heat insulation and cold insulation such as freezers, cool refrigerators, electric refrigerators, and frozen containers are usually obtained by a method such as in-situ foaming or in-situ spray foaming of a polyurethane foam resin. Alternatively, a heat insulating material obtained by laminating a foamed polyurethane resin with a surface material while continuously foaming the foamed polyurethane resin is used, for example, built in a main body of a freezer, a cool box, or a door.

[0003]

However, in the heat insulating material comprising only the foamed polyurethane resin layer, the thermal conductivity of the polyurethane resin itself is reduced by minimizing the size of bubbles. There is a limit from itself.

[0004] A heat insulating material consisting of only a foamed polyurethane resin layer has a problem in mechanical strength, and is inevitably used by laminating a metal thin film or the like.

[0005]

SUMMARY OF THE INVENTION The present invention relates to a foamed composite molded article having a low thermal conductivity, the gist of which is to cut or crush a used card having a plastic oriented sheet as a base material. There is provided a foamed composite molded article having a low thermal conductivity in which a metal body is embedded along a foamed molded article inside a foamed molded article formed by filling a strip with a foamable resin.

In addition, a metal body is formed into a foamed molded article inside a foamed molded article formed by filling a foamable resin with a card strip obtained by cutting or crushing a used card having a plastic oriented sheet as a base material. And a coating layer may be laminated on at least one surface thereof.

It is preferable that the weight ratio between the card strip and the foaming resin is in the range of 10: 1 to 3: 1.
Further, the foamable resin is preferably a room temperature foamed hard polyurethane resin.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail.

FIG. 1 is a cross-sectional view of one embodiment of a foamed composite molded article having a low thermal conductivity according to the present invention.
In a foam molded article 1 formed by filling a foamable resin 12 with a card strip 11 obtained by cutting or crushing a used card having a plastic orientation sheet as a base material,
The metal body 2 is embedded. The coating layer 3 is laminated on both surfaces.

The card strip is obtained by cutting or crushing a used card having a plastic oriented sheet as a base material.

The used cards are magnetic cards, and in many cases, a sheet of polyethylene terephthalate (hereinafter sometimes abbreviated as PET) biaxially stretched and heat-fixed is used as a base material. Highly molecularly oriented. A PET sheet having a thickness of about 200 μm is often used. A magnetic layer is formed on one surface (back surface), a protective layer is formed thereon, and a printed layer and a protective layer are formed on the other surface (front surface).

The used cards can be separated from the magnetic material if desired. However, the used cards can be used by simply performing a simple cleaning / drying process as needed without separating. The used cards are cut or crushed into small pieces for the purpose of being easily distributed evenly in the foamable resin, and being easily molded, and then reused.

When the size of the card strip to be cut or crushed is too small, the strength of the plastic oriented sheet base material itself is not utilized and the reinforcing effect is reduced. However, it is easy to achieve the planar arrangement as described later, but it is difficult to perform the molding process.

That is, the strength of the plastic oriented sheet base material itself is not utilized, and in some cases, fine pulverization having a diameter of 100 μm or less that causes a phenomenon such as melting and dissolving of the card strips by foaming resin is avoided. A size that can substantially maintain the molecular orientation and can be preferably arranged in layers along the plane direction, for example, 4 mm or less, preferably 4 mm to
The object can be achieved if it is reused in the form of a plate (chip) in which the ratio of length (width) / thickness (aspect ratio) is 5 or more.

In order to cut or crush used cards into card pieces, there are a method of cutting into a predetermined shape with a blade, and a method of crushing into an irregular shape with a crusher.

The foamable resin is a binder material (binding material), for example, various materials such as polyvinyl chloride, polyethylene, polypropylene, acrylonitrile butadiene-styrene resin (ABS resin), acrylic resin, and polyurethane. Can be used.

[0017] Among the foamable resins, polyurethane is preferred in terms of adhesiveness to the card strip. Since the polyurethane prepolymer is liquid at normal temperature, it is preferable because it can be mixed without melting the card strips. In particular, room temperature foamed hard polyurethane resin using water as a foaming agent,
Since foaming can be performed at room temperature, it is suitable from the viewpoint of molding a foamed composite molded article.

As the polyurethane resin, a diisocyanate component such as toluene diisocyanate or diphenylmethane diisocyanate and a polyol component such as polyester polyol or polyether polyol chain-extended with propylene oxide, ethylene oxide or the like are mixed at about 1: 1. Are preferably used. On the polyol side, a catalyst such as a tertiary amine such as triethylamine or tetramethylhexadiamine or an organic tin compound, or a foam stabilizer and a foaming agent such as polyether siloxane are added.

The foaming agent is not particularly limited as long as it does not deteriorate the foamable resin. For example, a chemical that generates gas by chemical decomposition such as azodicarbonamide or azobisisobutyronitrile is used. A blowing agent, or an organic gas having a boiling point equal to or lower than the melting point of a resin such as butane, pentane, dichlorodifluoromethane, monochlorodifluoroethane, or a volatile liquid, or carbon dioxide, nitrogen, air, argon, or neon. Inorganic gas, such as
Alternatively, use water or the like.

These may be used alone or in combination of two or more.

The foaming agent is preferably an inorganic gas or water from the viewpoint of safety and environmental protection. In particular, when it is desired to obtain a foaming agent having a high foaming ratio, a gas having a high solubility in a foamable resin such as carbon dioxide gas is used. In the case of a room temperature foamed hard polyurethane resin, water is preferable.

By using a foamable resin, a foamed composite molded article can be obtained with a small amount of resin, and an expanded composite molded article having a desired shape can be easily obtained by expansion during molding of the foamable resin. is there.

The filling amount of the card pieces is in the range of 10/1 to 3/1 by weight ratio of the card pieces / foamable resin, in other words, the total weight of the polyol component and the isocyanate component or the polyol component 1 Preferably, the card strip has a weight of 3 to 10 weight.

If the added amount of the card strip is more than 10/1, the integration of the card strip becomes insufficient and peeling or cracking tends to occur. When the number of card strips is less than 3/1, the effect of improving the mechanical strength of the obtained foamed composite molded article is small, and the filling amount of the card strips is large from the viewpoint of reusing used cards. Is preferred.

The addition of the card strips makes it possible to obtain a foamed composite molded article having high strength by taking advantage of the high strength of the plastic oriented sheet substrate. Further, in the case of a magnetic card or the like as used cards, it is not always necessary to separate a magnetic layer (material) formed on one surface (back surface), and it is possible to reuse the magnetic layer as it is. Further, the use weight of the binder material (binder) can be reduced by using the foamable resin.

The method of mixing the card strip and the foaming resin is not particularly limited. In the case of polyurethane, for example, a polyol, isocyanate, a foaming agent, etc. are uniformly mixed in advance, and the surface of the card strip is uniformly wetted with a liquid. Alternatively, a polyol (including a foaming agent) and an isocyanate may be separately discharged at a high speed by a spray gun, and then the mixture at the outlet may be atomized and applied to the surface of the card strip.

In the case of a room temperature foamed hard polyurethane resin, the card strip is added to a hopper of a fully meshing co-rotating twin screw extruder, and the mixed polyol, isocyanate and water as a foaming agent are extruded. It may be added and mixed from a central portion of the machine or a vent portion on the discharge port side, for example.

Generally, when a chemical blowing agent is used as a foaming agent, a single-screw or multi-screw extruder used for extrusion molding is used. In addition, when using a physical foaming agent such as an organic gas, a volatile liquid, an inorganic gas, and water, an extruder equipped with a vent-type screw and provided with an inlet through which the foaming agent can be pressed into the vent portion from the middle of the cylinder is used. used.

In particular, the fully meshing co-rotating twin screw extruder is suitable because it has a self-cleaning function in which the grooves of the screws rub against each other so that the mixture of the polyurethane resin and the card strips can be prevented from hardening at the stagnant portion.

When heating is required to mix the card strip and the foaming resin, the heating is performed at a temperature lower than the melting temperature of the plastic oriented sheet base so as not to impair the molecular orientation of the card strip. There is a need.

A metal body is embedded along the foamed molded article inside the foamed composite molded article having a low thermal conductivity of the present invention.

The metal body is made of a material having a high thermal conductivity, for example, an iron plate, a steel plate, an aluminum plate, a copper plate, etc., and there are no particular restrictions on the thickness and the number of sheets. Preferably about 0.2 to 1 mm
It is about three sheets.

The shape may be a flat plate, a corrugated plate, a plate having a large number of holes, a net, or the like.

Further, the metal body may be entirely buried in the foam molded article, or an end or a part of the surface of the metal body may be exposed.

A coating layer such as a woven fabric or a nonwoven fabric may be laminated on one surface or both surfaces of the foamed composite molded article having a low thermal conductivity of the present invention.

As the coating layer, a sheet-like material made by weaving or knitting a natural fiber, a synthetic fiber, or a fine wire metal, or a non-woven fabric or a polymer material made of such a material is used. What was molded into, further, depending on the application polyethylene, polypropylene,
Bonding metal materials such as sheets such as polyvinyl chloride and PET, iron plates, steel plates, aluminum plates, and copper plates to lower the thermal conductivity of the surface, improve the appearance, impart a metal appearance, The rigidity and the like may be further improved. Further, it is possible to prevent the foamed composite molded article from being damaged or damaged by external force during storage, transportation, construction and the like. In the case of a sheet or plate, these may be subjected to grain printing or painting, or if necessary, may be post-processed with holes of various diameters.

The non-woven fabric is made of any one or more of polyester fiber, polyethylene fiber, rayon fiber and glass fiber.
Those having 0 g / m ² are preferably used.

The thickness of the low thermal conductivity foamed composite molded article of the present invention is not particularly limited and can be arbitrarily set according to the purpose. Usually, the thickness of the foamed molded article of about 3 mm to 50 mm is 0.2 mm. Approximately 1 to 3 mm metal bodies are buried in 1 to 3 metal bodies, and 20 to 60 g / m ² of a woven or non-woven fabric is laminated as necessary. A composite molded article can be obtained, and a foamed composite molded article having a thickness of 5 mm or more, which has conventionally been considered difficult to be stretch-oriented, can be obtained. In this case, it is preferable to use a card strip having a relatively large area such as 5 mm square or more in terms of square shape.

For the lamination of the foam molded article and the metal body, or the foam molded article and the coating layer, for example, a solvent type adhesive, a solvent type rubber adhesive, a room temperature type hot melt adhesive, a heated type hot melt adhesive, etc. Is selected and used according to the purpose.

Forming the low thermal conductivity sheet or plate foam composite molded article of the present invention from a mixture of card pieces and foamable resin obtained by crushing used prepaid cards, etc., regulates the shape. And a method using a molding apparatus combining an extruder and a double conveyor type take-up machine.

In the former method using a molding die, for example, a molding die for regulating the shape is formed by a hollow box having a predetermined thickness, width and height. This hollow box type is used upright in the vertical direction, and has a resin pouring opening on the top surface. In addition, bottom plate, left and right side plate,
It is preferable to be able to assemble and disassemble into front and rear face plates, top face plates, and the like.

A metal body to be buried in the inside of the foamed molded body is disposed at the approximate center in the thickness direction inside the hollow box-shaped mold via a spacer. The material of the spacer is made of plastics, metal, ceramics, or the like.

In such a state, from the resin pouring opening,
A mixture of a foamed resin composed of a polyol, an isocyanate, and a foaming agent, which has been previously uniformly mixed, is dropped on the surface of a crushed card strip and uniformly wetted, and the mixture is filled so that the metal body is not biased to one side. After curing and foaming under predetermined conditions, the hollow box mold is disassembled as necessary to obtain a foamed composite molded article in which a metal body is embedded.

When the metal body is placed inside the hollow box as required, a coating layer with or without an adhesive is attached to the inner surface of the hollow box in a releasable manner. A covering layer may be applied to the surface of the placed and molded foam composite molded article.

The latter method using a molding device uses a molding device using a single-screw or multi-screw extruder and a double-conveyor type take-up machine consisting of a lower conveyor and an upper conveyor. The strips are fed into an extruder, mixed, and the mixture is extruded through an opening in the extruder barrel tip.

The mixture is first dropped into a gap formed by the upper surface of the lower conveyor and the lower surface of the metal body to be embedded in the foamed molded product, and immediately thereafter, the mixture is similarly removed from the metal body. Was dropped into the gap formed by the upper surface of the upper conveyor and the lower surface of the upper conveyor, and was moved and hardened and foamed while being sandwiched between the lower conveyor, the metal body, and the lower conveyor, and the metal body was buried when leaving the take-up machine. This is a method for obtaining a foamed composite molded article.

If necessary, a coating layer with or without an adhesive is interposed on the upper surface of the lower conveyor and the lower surface of the lower conveyor, and the coating layer is formed on the surface of the molded foam composite molded article. May be applied.

In the case of molding with an extruder, the extruder is usually extruded at the atmospheric pressure. However, if the extruded atmosphere is reduced in pressure from the atmospheric pressure, the foaming is completed quickly, and the bubbles become finer. .

[0049]

According to the present invention, a metal body is foamed inside a foamed molded product formed by filling a foamable resin with a card strip obtained by cutting or crushing a used card having the plastic oriented sheet of the present invention as a base material. The foam composite molded body with low thermal conductivity embedded along the molded body has low thermal conductivity, and since this low thermal conductivity is maintained for a long period of time, such as freezer, cold storage, electric refrigerator, freezing container, etc. It is useful as a heat insulation / insulation material.

Further, since the metal body is embedded inside the foamed molded body along the foamed molded body, the foamed molded body is obtained by cutting or crushing used cards having a plastic oriented sheet as a base material. Due to the configuration of the card strips and the foaming resin, the orientation structure of the plastic orientation sheet base material is utilized as it is to have high strength, and at the same time, a foam composite molded article by a metal body embedded therein. It will be of high overall strength.

By using a foamable resin as a binder, a foamed molded article can be obtained with a relatively small amount of binder.

Further, in reproducing the used cards, it is not always necessary to separate the magnetic material on the surface of the cards, and the used cards can be reprocessed as they are. This can be greatly simplified, and there is no generation of a substance that needs to be treated again, which is preferable from the viewpoint of environmental conservation.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a specific example of a foam composite molded article according to the present invention.

[Explanation of symbols]

 A foam composite molded article 1 foam molded article 11 card strip 12 foamable resin 2 metal body 3 coating layer

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI B29K 105: 26

Claims (4)

[Claims] A metal body is formed into a foamed molded article formed by filling a foamed resin with a card strip obtained by cutting or crushing a used card having a plastic oriented sheet as a base material. A foamed composite molded article having a low thermal conductivity, which is buried along. 2. A metal molded body formed inside a foamed molded article formed by filling a foamable resin with a card strip obtained by cutting or crushing a used card having a plastic oriented sheet as a base material. A foamed composite molded article having a low thermal conductivity, wherein the molded article is embedded along the surface and has a coating layer laminated on at least one surface thereof. 3. The foam composite molding with low thermal conductivity according to claim 1, wherein the weight ratio between the card strip and the foamable resin is in the range of 10: 1 to 3: 1. body. 4. The foamed composite molded article having a low thermal conductivity according to claim 1, wherein the foamable resin is a room temperature foamed hard polyurethane resin.