JPH1071886A - Carpet having under cushion and forming method of under cushion - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form high density by forming a high density part whose density is partially heightened in an under cushion, and pressing and burying it in the timing when a foaming resin raw material of a high density prescribed part is not hardened. SOLUTION: A coating film 21 of a heat resistant resin film or nonwoven fabric is arranged on the reverse 20b of a carpet, and oozing-out of a foaming resin raw material to the carpet side is prevented. Among an under cushion 30, a partial specific area is formed as a high density part 31. Density of this high density part is 0.10 to 0.50g/cm<3> , and the density is higher by two times or more than a general part 32. Particularly, a density change from the general part is sharply caused. A temperature of an upper mold of an injection molding mold is heightened to 50 deg.C or more, and a temperature of a lower mold is cooled to the normal temperature, and foaming reaction is advanced sufficiently faster on the upper mold side (particularly, in an excess part) than the lower mold side. Therefore, on the lower mold side where foaming reaction (hardening and polymerization) is delayed, a foaming cell is intensively compressed by a press from above, and is formed as a high density part whose density is higher than the other part.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a carpet provided with an under cushion made of a resin foam on the back surface and a method for forming the under cushion.

[0002]

2. Description of the Related Art Conventionally, an under cushion made of a resin foam is provided on a back surface of a carpet laid on a floor panel of an automobile or the like. For example, actual fairness 4-42
No. 111 relates to a method of forming this kind of undercushion, using an injection mold, disposing a carpet in the injection mold, injecting a foamable resin material into the back of the carpet, and forming a resin foam undercushion. Has formed. In the case of car floor carpets laid on car floor panels, the formation of an under cushion improves sound insulation against noise from the direction of the floor panel, and follows the shape along the floor panel with many fine irregularities In addition, it is possible to obtain an improved cushioning property and an appropriate cushioning property when the occupant puts his / her foot on the carpet. For the purpose, the degree of foaming (hardness, density) of the undercushion can be more highly achieved by changing the distribution as needed than by making it uniform. In particular, in the case of floor carpets for automobiles, the use varies depending on the site even within the same floor carpet. In general, it is suitable to make the back side of the carpet hard and increase the density. Therefore, even in the above-mentioned Japanese Utility Model Publication No. 4-42111, a floor carpet having a synthetic resin foam layer on the back surface “the apparent density of the foam layer continuously decreases in the thickness direction from the back surface of the floor carpet toward the body iron plate” is described. Proposed. In this case, the foaming ratio is continuously varied by adjusting the temperature of the foaming mold or adjusting the distribution of the foaming agent, but the mold temperature and the like for stably and accurately achieving the target foaming ratio are improved. Difficult to set up and control. Further, since the change in the expansion ratio occurs continuously and slowly, the degree of expansion (density) in a specific region cannot be changed sharply.

[0003]

SUMMARY OF THE INVENTION In view of the above-mentioned problems, the present invention provides a carpet having an under cushion made of a resin foam on the back surface, in which the density of a specific portion of the under cushion is sharper than other portions. Provided is a method for forming a carpet with an increased underaction and an undercushion for accurately and stably increasing the density of a specific target area.

[0004]

Means for Solving the Problems A means of the present invention is a carpet provided with an under cushion made of a resin foam on the back surface, wherein the under cushion has a partially increased density. A carpet with an undercushion forming a portion, and a method of forming an undercushion, wherein the shape of a cavity formed at the time of mold clamping is substantially equal to a target undercushion, and a base portion. Using an injection mold consisting of an extra shape part that protrudes, the carpet is placed between the injection molds with the back side facing the cavity, the mold is closed, and the foamable resin material is injected into the cavity, and the inside of the cavity is injected. A foaming reaction is caused in the cavity, and the inside of the cavity is filled with the foaming resin material, and the foaming resin material is sufficiently cured in the surplus portion, while the base shape is At the timing when the foamable resin material is uncured, the foamable resin material in the surplus portion of the cavity is pressed into the base portion of the cavity and buried, thereby forming a high density portion in the under cushion to the back of the carpet Depending on the method of forming the under cushion.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a carpet 10 with an undercushion according to the present invention.
The under cushion 30 is integrally formed on the back surface of. The carpet 20 is a well-known tuft carpet or needle punch carpet, and the design of the surface 20a is enhanced by piles and raised hairs. On the back surface 20b of the carpet, a coating 2 of a heat-resistant resin film or non-woven fabric
It is preferable to prevent the leaching of the foamable resin raw material to the carpet side by adding a step (1).

As the under cushion 30, polyurethane foam is most suitable. Part of the specific area of the under cushion is formed in the high density portion 31. The density of this high density part is 0.10 to 0.50 g / cm
³ , which is preferably at least twice as high as the density of the general portion 32, and particularly preferably the density change from the general portion is sharp. The high-density portion can be formed at any position in the spreading direction of the carpet, but in the thickness direction,
Preferably, it is formed close to the back side of the carpet.

Next, a method of forming an under cushion having such a high-density portion on the back surface of a carpet will be described. FIG. 2 shows an injection molding die 40 for forming an under cushion suitable for the present invention. The injection mold includes an upper mold 41 and a lower mold 42, and is clamped with a required cavity 45. In the mold open state, the preformed (or unformed) carpet 20 is formed on the lower mold 42.
The mold is clamped by disposing the back surface with the coating 21 upward facing upward. The cavity 45 formed between the upper and lower molds and the back of the carpet by this mold clamping has a base portion 45a along the target under cushion and an extra shape portion 45b of a size protruding from the base portion on the upper die side. I have it. The thickness of the surplus portion is preferably at least twice the thickness of the base portion.

In such a mold clamping state, a urethane foam raw material (foamable resin raw material) is injected into the cavity to start a foaming reaction. This is a reaction using a polyol, an isocyanate, and a foaming aid. The raw material fills the cavity while a polymerization reaction and a crosslinking reaction of the resin occur simultaneously with the foaming reaction. Each of these reactions proceeds in a well-balanced manner and is completed to form a foam (under cushion) along the cavity shape. The progress of the reaction strongly depends on the ambient temperature, and the progress of the reaction is faster when the mold temperature is set higher in a certain range. In the present invention, the temperature of the injection mold upper mold 41 having the extra mold is raised to 50 ° C. or more, and the temperature of the lower mold 42 is cooled to room temperature, and the foaming reaction is performed on the upper mold side (particularly, the extra mold). Make sure to proceed much faster than the lower mold.

FIG. 4 schematically shows this situation. In this type of reaction, the degree of progress of the reaction is generally expressed in terms of appearance in the order of cream time t ₁ , rise time t ₂ , tack-free time t ₃ , and cure time t ₄ in order from the start of the reaction. It is. The foaming reaction apparently starts from the cream time t ₁ and rapidly progresses from the rise time t ₂ . Until the tack-free time t ₃ , the resin remains plastic and easily deforms, but after the cure time t ₄ , the foaming reaction, cross-linking reaction, and polymerization reaction are almost completed, and the resin hardens and does not easily deform. In the present invention, as shown in FIG. 4, the progress of the reaction in the surplus portion on the upper mold side is about 1.2 to 2 times faster than that in the base portion on the lower mold side. There is a stage where the tack free time or cure time is reached at the (remaining part), while the tack free time or cure time is not reached on the lower mold side. Can be buried in the general part. The foaming reaction (curing,
On the lower mold side where polymerization is delayed, the foam cells are intensively compressed by pressing from above, and a high-density portion whose density is significantly higher than other portions is formed. Pressing of the surplus portion can be performed outside the mold by removing the under-cushioned carpet from the casting mold, but it is preferable to use a pressing means integral with the casting mold. Preferred as this type of pressing means are a method of providing a movable plate 43 and a pressing device 44 in a mold and compressing the same, and a method of providing a high-pressure gas inlet 46 and compressing the gas.

[0010]

【Example】

(Example 1) As a carpet, a known nylon tufted carpet in which a nylon thread was tufted on a base cloth was used, and a film (a polyamide,
(Thickness: 0.1 mm), and placed between the injection molds with the back surface facing upward. The injection mold forms a cavity inside in a closed state. The shape of this cavity is 500 width
mm, depth 500 mm, thickness 10 mm, protruding from the base, width 100 mm, depth 100 mm, thickness
It has an extra shape of 20 mm. The underaction is formed by injecting A, B, and two-pack type urethane resin into the cavity and foam molding. Liquid A was prepared by adding a blowing agent, activator, and auxiliary agent for a foam stabilizer to a polyether-based polyol, and liquid B was an MDI-based isocyanate resin. The upper mold temperature is set to 60 ° C and the lower mold temperature is set to 20 ° C.
Is set, the urethane resin is injected into the cavity, and a foaming reaction with a foaming ratio of 15 is performed to fill the cavity.

In this blending and the reaction under the mold temperature,
The cream time t ₁ , rise time t ₂ , tack-free time t ₃ , and cure time t ₄ of the urethane resin in the surplus portion of the cavity are 6 seconds, 60 seconds, and 1 respectively.
00 seconds and 180 seconds. On the other hand, at the base of the cavity, t ₁ ′, t ₂ ′, t ₃ ′, t ₄ ′ are each 10 seconds,
80 seconds, 200 seconds and 260 seconds. At the stage of 120 seconds when the augment is between the tack free time and the cure time, and when the base is between the rise time and the tack free time, press the upper part of the augment by 20 mm from above, and The shape was buried in the general part. (Comparative Example) In the comparative example, the material and the molding conditions (cavity shape) are the same as those in the example, but the extra shape portion is not pushed into the general portion.

(Results) FIG. 3 shows the density distribution in the cross section in the thickness direction and the cross section in the spreading direction of the under cushion. In the thickness direction, the density is 0.10-0.
At 25, a high-density portion having a density at least twice as high as that of a general portion is formed. In the high-density portion, the density was increased twice or more in the spreading direction as compared to the general portion, and the boundary between the high-density portion and the general portion was sharply formed.

[0013]

According to the present invention, a high-density portion can be sharply formed inside an under cushion of a carpet having an under cushion on the back surface.

[Brief description of the drawings]

FIG. 1 shows a carpet with an under cushion according to the present invention.

FIG. 2 shows an injection mold for an under cushion.

FIG. 3 shows a density distribution of an under cushion.

FIG. 4 shows the change over time of foam molding.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Carpet with an under cushion 20 ... Carpet 20a ... Front 20b ... Back 21 ... Film and coating 30 ... Under cushion 31 ... High density part 32 ... General part 40 ...・ Injection mold 41 ・ ・ ・ Upper mold 42 ・ ・ ・ Lower mold 45 ・ ・ ・ Cavity 45a ・ ・ Base part 45b

Claims (2)

[Claims] 1. A carpet provided with an under cushion made of a resin foam on a back surface, wherein the under cushion has a high-density portion having a partially increased density. carpet. 2. A method for forming an undercushion made of a resin foam on the back surface of a carpet, comprising: a base having a shape of a cavity formed at the time of mold clamping substantially equal to a target undercushion; Using an injection mold consisting of a surplus part with a shape protruding from the shape part, arranging the carpet between the injection molds with the back side facing the cavity, clamping the mold, injecting the foamable resin raw material into the cavity,
At the timing when the foaming reaction is caused in the cavity and the inside of the cavity is filled with the foamable resin material, the foamable resin material is sufficiently cured in the surplus portion, while the foamable resin material is uncured in the base portion. Pressing the foamable resin material in the surplus portion of the cavity into the base portion of the cavity,
A method for forming an undercushion on the backside of a carpet, characterized by forming a high-density portion in the undercushion by burying the undercushion.