JPS6362387B2 - - Google Patents

Description

Detailed Description of the Invention [Technical Field of the Invention] The present invention relates to a method for producing a foam molded product using pieces of a foam or its waste material, and particularly relates to a method for manufacturing a foam molded product using pieces of a foam such as urethane or its waste material. A mixture of natural or synthetic fibers, pulp, vinyl chloride, vinyl leather, or glass fiber scraps is bonded with a thermoplastic synthetic resin binder, heated and pressure-molded, and then dried and cooled. The present invention relates to a method for manufacturing a sound absorbing and insulating molded article.

[Prior art and its problems]

Conventional sound absorbing and insulating moldings are made by mixing urethane foam or scrap pieces of natural and synthetic fibers, uniformly applying a thermosetting urethane solution to this mixture, and weighing a certain amount of the mixture to mold it. The mixture is filled into a mold, heated steam is passed through the mold to harden the thermosetting urethane, the mixture is solidified and molded, and the molded product is removed from the mold and then dried to remove moisture. .

However, this conventional manufacturing method requires a long time for curing and drying due to the curing reaction using heated steam. In addition, the thermosetting urethane solution used as a binder is expensive and has high reactivity, so when additives such as modifiers and fillers that have sound absorbing and damping effects are added, the solution becomes unstable. adversely affect the characteristics and characteristics.

Additionally, when feeding scrap strips into the molds, the strips must be weighed for each mold and then manipulated by the operator to ensure that the strips are evenly distributed throughout each part of the mold. No. Alternatively, the product is manufactured by making a large block-shaped molded product in advance and cutting it.

Therefore, when mass producing molded products, there are many work steps, it takes a long time to manufacture one product unit, the quality varies widely, and the organic solvent gas contained in the urethane solution of the binder is used during the work. There are disadvantages such as the occurrence of Also, the products are expensive. For this reason, conventional manufacturing methods have been limited to applications such as parts suitable for relatively small quantity production such as specially equipped vehicles, or relatively simple-shaped parts that can be cut from large block-shaped molded products.

[Purpose of the invention]

The present invention was made to solve these problems, and its purpose is to utilize the characteristics of thermoplastic synthetic resin binders to make it suitable for mass production, with fewer work steps, and to reduce manufacturing time. It is an object of the present invention to provide a method for producing an inexpensive sound-absorbing and insulating molded product that is short, has small variations in quality, and has excellent sound-absorbing and insulating effects.

[Summary of the invention]

The method for producing a sound absorbing and insulating molded product of the present invention involves mixing strips of urethane foam or its waste material with strips of flexible waste material such as cloth, and adhering a thermoplastic synthetic resin binder to the surface of the strip. The method is characterized in that after the molded product is formed by heating and pressure molding, the molded product is dried and cooled by blowing or suctioning air.

The thermoplastic synthetic resin binder used in the present invention is composed of a single or copolymer self-crosslinked, reactive or modified vinyl acetate, acrylic ester, or ethylene vinyl acetate emulsion with water. PH adjustment is extremely easy, and various modifiers or fillers can be added in high proportions depending on the purpose.

The binder spreads deeply into the gaps between each strip, and when the water gradually evaporates at low temperatures, it gels and becomes sticky, and even with slight heating and pressure, it can be molded into any shape. It is possible to hold the

Preferably, in the present invention, the mixture of strips is preformed into a certain shape using a thermoplastic synthetic resin binder, and the preform is heated at high temperature and pressurized for a short time to soften the binder, The strip mixture in the mold is easily conformed to the shape of the mold, and the portions protruding from the mold are cut off at the edges of the mold. In addition, by taking advantage of the high air permeability of the molded product, air is blown into or suctioned from the molded product to remove moisture and cool and solidify the binder, resulting in stable dimensions and shape after demolding. A sound absorbing and insulating molded product with excellent properties is produced.

[Description of preferred embodiment]

Next, details of the method for manufacturing the sound absorbing and insulating molded article of the present invention will be explained based on a first example.

First, pieces of urethane foam or its waste material and pieces of flexible waste material are each crushed to a certain size. Foam or pieces of waste material are scraps or scraps of foam produced in the manufacturing process of various urethane foam products, and are crushed to a diameter of approximately 8 mm, although this varies depending on the purpose of use. It is preferable to do so. Small pieces of flexible waste material are scraps or waste materials such as fibers such as cloth, pulp, vinyl chloride, vinyl leather, or quilting scraps of filler pads, and the diameter of these pieces varies depending on the purpose of use. It is preferable to crush it to about 13 mm. Equal weights of pieces of crushed foam or its waste material and pieces of flexible waste material are mixed together in a container, and the thermoplastic synthetic resin binder is evenly applied to the mixture of these pieces while stirring. .

The mixing ratio of the foam or its waste material strips and the flexible waste material strips is most preferably equal weight, but any ratio may be used depending on the purpose. The mold may be of any shape, but must have openings for blowing or suctioning air.

The thermoplastic synthetic resin binder is a self-crosslinking type, a reactive type, or a modified type of vinyl acetate as a single substance or a copolymer,
It consists of an emulsion of acrylic ester or ethylene vinyl acetate, etc., and water. A modifier such as calcium carbonate and/or a filler such as diatomaceous earth or clay can be added to this emulsion. The binder is preferably one in which 15 to 20 g of calcium carbonate is added to an emulsion in which 55 g of ethylene vinyl acetate emulsion copolymer is suspended in 0.5 to 10 micron particles in 45 g of water. In this case, the total weight of the binder applied is preferably 20 to 25% of the weight of the strip mixture, but may vary depending on the suspension concentration of the binder. It is desirable to adjust the pH of the binder to 6.5 to 7.5. The method of application is most preferably by spraying, but it may also be applied by dipping the strips in the binder. However, it is desirable to apply the binder so that there are sufficient gaps between each strip to allow air to pass through.

After the strip mixture to which the binder is attached is placed in a mold, the mold is closed and the strip mixture is heated and pressure-molded to form a molded product. This heating and pressurization is approximately
A temperature of 150 to 200°C and a temperature of about 10 to 80 kg/cm ² for about 2 minutes is suitable.

Next, by blowing air into or suctioning air from the openings provided in the mold, air is blown into or suctioned from the gaps in the molded product after heating and pressurization. The molded article is cooled by evaporating the moisture in the binder and removing the heat of vaporization.

In order to cool the molded product, instead of venting through the openings as described above, the molded product that is pressurized between the upper and lower molds needs to be vented from the side of the thick part of the mold as appropriate. This may also be done by using a device to force air into the gaps between the strips.

After drying and cooling, the manufactured sound absorbing and insulating molded product is removed from the mold.

According to the present invention, after adhering a binder to the surface of the strips, the strips are pre-dried and placed in a mold, a skin layer is laminated on the top surface of the strip mixture with the binder interposed therebetween, and the strips are placed in the mold. By heating and pressing the piece and this skin layer, it is possible to provide the molding with an integral skin layer.

The skin layer is preferably a vinyl chloride sheet, a rubber sheet, an asphalt sheet, or a combination of two or more of these sheets. The skin layer has the effect of improving the sound insulation properties of the molded product.

Next, details of a second embodiment of the method for manufacturing a sound absorbing and insulating molded article of the present invention will be described with reference to FIG.

FIG. 1 is a sectional view of a mold for obtaining a final product by molding. This mold 1 includes an upper mold 3 having a molding uneven part 31 on the lower surface and a molding uneven part 4 on the upper surface.
It consists of a lower mold 4 with a mold 1 provided thereon. The diameter D of the upper mold 3 is slightly larger than the diameter D' of the lower mold 4, and the upper mold 3 and the lower mold 4 mesh with each other. The interlocking edges E and E' of the upper mold 3 and lower mold 4 are sharp and suitable for cutting. The upper mold 3 has a hot plate 35 in the upper layer,
Further, a heat insulating layer 36 is provided above the hot plate 35 to block heat from the hot plate 35. The lower mold 4 has inside thereof a passage 42 for passing air and an air blowing hole 43 for communicating air from the passage to the uneven portion 41. A hot plate 45 is provided below the passage 42, and a heat insulating layer 46 is further provided below the hot plate 45.

First, a thermoplastic synthetic resin binder is applied to the strip mixture in the same manner as in the first embodiment. While stirring the mixture of strips to which the binder is attached, water at a temperature of 50°C or less is blown into the gaps between each of the strips of the mixture, or by suctioning air therefrom, to gradually remove water from the binder. The bonding agent adhering to the strips is then gelled to provide adhesive strength. This mixture of strips is preformed into a plate-like preform 5 having a thickness about 1.5 times the thickness of the final product using a hot press or a hot roll (not shown). The preform 5 may be formed to such an extent that it can maintain its shape when fed onto the mold shown in FIG.

The preform 5 is placed on the lower mold 4 whose temperature is adjusted to about 200° C. by the hot plate 45 . Furthermore, a vinyl chloride sheet 6 is placed on the upper surface of the preform 5 with the same thermoplastic synthetic resin binder 7 as described above interposed therebetween. This vinyl chloride sheet 6 is heated to approximately 100 to 130°C by infrared rays or a hot air oven in order to facilitate molding.
It is preferable to heat it to. The sheet 6 may also contain a modifier such as calcium carbonate. next,
By closing the upper mold 3 adjusted to about 150° C. by the hot plate 35 onto the lower mold 4, the edge E of the upper mold 3 and the edge E' of the lower mold 4 are engaged, and the preform 5 is formed.
Then, the sheet 6 is cut to the mold size, and the preform 5 and the sheet 6 sandwiched between the upper mold 3 and the lower mold are integrally molded under heat and pressure. Pressurization is preferably performed at a pressure of about 10 to 80 kg/cm ² and for a duration of about 1.5 to 3.0 minutes. This molding can be performed by deep drawing.

Next, by sending air to the passage 42 provided in the lower mold 4, approximately 100 ml of air is introduced into the preform 5 sandwiched between the upper mold 3 and the lower mold 4 through the air blowing hole 43.
Blow air for ~20 seconds to remove moisture in the binder and cool the molding.

After drying and cooling, the manufactured sound absorbing and insulating molded product is removed from the mold.

The sound absorbing and insulating molded product produced weighs approximately 0.1 to 0.5 kg/
^cm2 is preferred.

FIG. 2 is a graph showing the sound insulating effect of the sound absorbing and insulating molded product manufactured according to the present invention on a C scale and an A scale.

The horizontal axis indicates 1/3 octave frequency (Hz) for the C scale, and full-range transmission for the A scale. The vertical axis shows the sound pressure level (dB).

In the C scale, the broken line indicates the sound pressure of a conventional product manufactured using thermosetting urethane as a binder, and the solid line indicates the sound pressure of a sound absorbing and insulating molded product manufactured using a thermoplastic binder according to the manufacturing method of the present invention. Indicates level. The product of this invention is 200Hz (line a) compared to the conventional product.
It is clearly shown that the transmission loss is large between 1250Hz and 1250Hz (line b), and it is recognized that the sound insulation properties are excellent. In particular, it should be noted that in the low frequency range (approximately 1000 Hz or less), which is most perceptible to human hearing, the transmission loss of the product of the present invention is significantly greater than that of conventional products, and its sound insulation properties are excellent. be.

In addition, regarding the A scale, the sound absorbing and insulating molded product manufactured by the present invention has better sound insulating properties than conventional products even at the A characteristic point, which is the noise regulation value specified by JIS. is recognized from the graph.

〔Effect of the invention〕

As explained above, according to the present invention, it is extremely easy to adjust the viscosity and PH as a binder compared to the conventional method using a thermosetting urethane solution as a binder, and the addition of a modifier or filler can be used as a binder. Because it uses a thermoplastic synthetic resin binder that can be Are better.

Furthermore, according to the present invention, the molded product is cooled and dried by blowing air between the small pieces or suctioned therefrom, and is sufficiently hardened before being demolded, so that the dimensional stability of the molded product after demolding is improved. This improves molding time and reduces molding time. Furthermore, according to the embodiment in which the preform is continuously supplied to the mold for molding, it is possible to efficiently mass-produce molded products of stable quality in a small number of work steps and in a short manufacturing time. Therefore, the present invention can be applied to the economical, stable, mass production of foams used in a wide range of fields in addition to sound absorbing and insulating products as automobile parts, and has significant effects. be.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of a mold used in an embodiment of molding a final molded product from a preform according to the method of the present invention. FIG. 2 is a graph showing the sound insulation effect of the sound absorbing and insulation molded product manufactured by the method of the present invention. [Main symbols], 1...Mold, 3...Upper mold, 4...
... lower mold, 5 ... preform, 6 ... vinyl chloride sheet, 42 ... passage, 43 ... air blowing hole.

Claims (1)

[Claims] 1. (a) After adhering a thermoplastic synthetic resin binder to the surface of a strip of foam or its waste material, the strip is placed in a mold; (b) said mold is closed; (c) drying and cooling the molding by blowing or suctioning air into the spaces within the molding; (d) then A method for producing a foam molded article, which comprises demolding the molded article. 2. A method as set forth in claim 1, in which a thermoplastic synthetic resin binder is attached to a foam or a piece of its waste material, and the mixture is pre-dried before being placed in a mold. 3. The method described in claim 1, wherein the thermoplastic synthetic resin binder is a single or copolymer self-crosslinking, reactive or modified vinyl acetate, acrylic ester or ethylene acetate. A method for producing a foam molded product made of an emulsion of vinyl and water. 4. The method according to claim 1, 2, or 3, wherein the thermoplastic synthetic resin binder contains a sound absorbing and insulating modifier and/or a filler. 5. The method according to claim 1, 2, 3, or 4, wherein the strip with the binder adhered to the surface is placed in a mold, and the thermoplastic synthetic resin is placed on the upper surface of the strip. A method for manufacturing a foam molded article, which comprises laminating skin layers with a binder interposed therebetween, and heating and press-molding the strips and the skin layers in the mold. 6 (a) by applying a thermoplastic synthetic resin binder to the surface of the foam or its waste strips; (b) by forcing heated air through the strips; Dry the binder to such an extent that the binder has adhesive strength, (c) Preform the strips into a plate of a certain thickness, and (d) Place the preform in a mold and heat and heat. A foam molded product, characterized in that the molded product is formed by pressure molding, and (e) the molded product is further dried and cooled by blowing or suctioning air into the space within the molded product. Production method. 7. The method according to claim 6, wherein after preforming, a skin layer is laminated on the top surface of the preform with the thermoplastic synthetic resin binder interposed therebetween, and the preform is 1. A method for producing a foam molded article, the method comprising heating and pressure molding the article and the skin layer.