JPS6330436B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method of manufacturing a sound insulating carpet for a vehicle. More specifically, the present invention relates to a method for manufacturing an automobile carpet that is flexible, has excellent sound insulation effects, and has sufficient suture removal strength. Carpets for automobiles are widely used as interior materials that have decorative effects, dustproofing effects, and soundproofing effects for the interior of cars.Currently, carpets made of low-density polyethylene backed by lamination are mainly used to smooth uneven car floors. Press-molded to fit,
Commonly used. In recent years, there has been a demand for carpets with better sound insulation performance for the purpose of lowering the noise level inside automobiles and improving livability. In order to meet this demand, carpets lined with thick sheets of ethylene/vinyl acetate copolymer resin containing inorganic fillers have recently been put into practical use. In this case, it is preferable to increase the content of the inorganic filler as much as possible in order to increase the sound insulation performance and reduce the material cost. There were disadvantages in that it was difficult to remove and the thread removal strength (pulling strength of the pile) decreased when it was lined with carpet. As a result of intensive studies on how to improve this drawback, the present inventor applied coextrusion technology to extrude a main layer with a high content of inorganic filler and a sublayer with a low content of inorganic filler. Even if a single layer of resin with a high content of inorganic filler is used, when it is laminated so that it is in contact with the back side of the carpet, the ease of taking off the molten sheet from the T-die and the strength of the thread removal are improved compared to the case of extrusion backing. I found out what I can do. That is, the present invention comprises a first thermoplastic synthetic resin containing 65-95% of an inorganic filler and 0-65% of an inorganic filler.
A second thermoplastic synthetic resin containing The present invention provides a method for producing a sound insulating carpet, which is characterized in that the back surface of an original fabric is crimped with a roll. The thermoplastic synthetic resin referred to in the present invention is 50-200
Polymers that melt and fluidize at °C, such as polyolefins such as polyethylene, polypropylene, and polybutene, ethylene propylene copolymers, ethylene butene copolymers, and ethylene/4-methylpentene.
Ethylene/α-olefin copolymers such as 1 copolymer, ethylene vinyl ester copolymers such as ethylene vinyl acetate copolymer, ethylene vinyl propionate copolymer, ethylene methyl acrylate, ethylene ethyl acrylate, ethylene acrylic acid Ethylene/unsaturated carboxylic acid ester copolymers such as butyl, ethylene methyl methacrylate, ethylene unsaturated carboxylic acid copolymers such as ethylene acrylic acid, ethylene methacrylic acid, and their ionomers ethylene/vinyl ester/unsaturated carboxylic acid Terpolymers, ethylene/unsaturated carboxylic acid ester/unsaturated carboxylic acid terpolymers, other 1,2-polybutadiene, styrene/butadiene copolymers, styrene/isoprene copolymers, plasticized polyvinyl chloride, etc. means. Among these, ethylene/vinyl ester copolymers and ethylene/unsaturated carboxylic acid ester copolymers are most preferred in terms of fillability, flexibility, processability, economic efficiency, and the like. Particularly preferred is ethylene vinyl acetate copolymer. The comonomer content of these copolymers is 5-50% by weight, preferably 10-40% by weight, and the melt index is
0.1-500 dg/min, preferably 1-150 dg/min is suitable. Particularly preferred are ethylene vinyl acetate copolymers having a vinyl acetate content of 20-35% by weight and a melt index of 1-30. If a copolymer having a comonomer content of less than 5% by weight is used, when a large amount of inorganic filler is mixed, the rigidity will increase and the strength and processability will decrease. On the other hand, if a copolymer with a comonomer content of 50% by weight or more is used, heat resistance and shape retention will deteriorate. Furthermore, it is not preferable that the melt index of the copolymer is less than 0.1 dg/min or more than 500 dg/min because problems will arise in the formability of the T-die sheet. The inorganic filler used in the present invention is a fine particulate filler that can increase density and impart sound insulation properties when mixed with the thermoplastic synthetic resin, such as calcium carbonate, calcium oxide, calcium sulfate, calcium fluoride, etc. Magnesium oxide, magnesium carbonate, magnesium silicate, barium sulfate, aluminum sulfate, aluminum hydroxide, silica, clay, talc, zinc white, dolomite, mica powder, diatomaceous earth, alumina white, asbestos, pumice powder, graphite, iron powder, iron oxide powder, etc. Among these, particularly preferred inorganic fillers include calcium carbonate and barium sulfate because of their high filling properties and excellent economic efficiency. The mixing ratio of the inorganic filler to the thermoplastic synthetic resin is different between the main layer, that is, the layer made of the first thermoplastic synthetic resin, and the sublayer, that is, the layer that is made of the second thermoplastic synthetic resin. 50-95% preferably 60-90% for the main layer and 0-80%, preferably 0-65% for the subordinate layer. As the proportion of inorganic filler in the main layer increases, the density of the compound increases.
This improves the sound insulation effect and is generally economically advantageous. Therefore, it is better to increase the blending ratio of the inorganic filler unless problems arise with the extrudability or mechanical properties of the sheet. On the other hand, if the blending ratio of the inorganic filler in the secondary layer is too high, the removal strength of the carpet will decrease and the reinforcing effect on the main layer will be weakened. Unless economic efficiency is considered, it can be said that it is better not to include an inorganic filler. The required thickness of the sublayer varies depending on the pile of the carpet, the type of base fabric, and the amount of inorganic filler mixed, but it is generally at least 100 μm, preferably 200 μm.
−400 μm. If it becomes too thin, the removal strength of the carpet and the reinforcing effect on the main layer will be insufficient. The layer thickness ratio between the main layer and the subordinate layer is preferably 98-50:2-50. Of course, in addition to the thermoplastic synthetic resin and inorganic filler, paraffin wax, microcrystalline wax,
Low molecular weight polyolefins such as polyethylene wax and attack polypropylene, process oils, liquid modifiers such as plasticizers, etc. can also be mixed. It is also possible to mix rosin and rosin derivatives, tackifier resins such as terpene resins, petroleum resins, or asphalt in the subordinate layer for the purpose of improving the adhesion to the carpet pile and base fabric. The method of mixing the thermoplastic synthetic resin and the inorganic filler is not particularly specified. Single screw extruder, twin screw extruder,
A Banbury mixer, a continuous intensive mixer, etc. may be used. It is also possible to use granules in which the above-mentioned low molecular weight polyolefin is used as a binder and an inorganic filler is pre-agglomerated. In this case, pellets of thermoplastic synthetic resin and the granular aggregates are dry blended, and a coextruder is used. It is sufficient to supply it to the hopper. The T-die coextruder used in the present invention is not special, and a machine generally used for molding coextruded sheets of thermoplastic synthetic resins is used. The coextrusion apparatus may be either a black box type or a multi-manifold type, but it is preferable to use the latter because the melt viscosities and layer thicknesses of the main layer and the sublayer often differ considerably. The coextruded sheet extruded from the T-die is sent to a cooling roll, where a sound insulating carpet is formed by pressing the subordinate layer of the sheet and the back surface of the carpet material with a roll. Molding of such a coextruded sheet is less likely to cause breakage of the molten sheet than when molding only the main layer as a single layer, making it easier to take off the sheet.
Molding speed can be increased. Furthermore, the strength of the sound insulating carpet to be removed is also improved compared to the case where only the main layer is used. Furthermore, by forming multiple layers in this way, it is possible to increase the average content of inorganic filler in all layers of the sheet, resulting in more flexibility and
This not only provides a sound insulating carpet with superior sound insulating performance, but also has the advantage of reducing sheet material costs. Next, the effects of the present invention will be shown through examples, and the ingredients of the resins for the main layer and the sublayer used here are shown below. Γ Evaflex (Mitsui Polychemical's ethylene vinyl acetate copolymer resin) 150 (Melt index 30, vinyl acetate 33% by weight) 250 (Melt index 15, vinyl acetate 28% by weight) 360 (Melt index 2, vinyl acetate 25% by weight) 450 (melt index 15, vinyl acetate 19% by weight) Γ Sunthene 2100 (extender oil manufactured by Sunoil Co., Ltd.) Examples 1 to 5 A 90φ extruder (for main layer) equipped with a multi-manifold type coextrusion die and 40φ extruder (for slave layer)
Using a coextrusion sheet molding machine consisting of, extrude a coextrusion sheet with a main layer of 1.8 mm and a subordinate layer of 0.2 mm using the resin for the main layer and the resin for the subordinate layer of the composition shown in Table 1,
A raw fabric of nylon tufted carpet with jute as a base fabric was laminated on a cooling roll. The molten sheets had good pullability, and the resulting sound-insulating carpets had a thread removal strength of 2 kg or more, making it difficult to pull out the piles by hand. Comparative Examples 1 to 4 In Examples 1 to 5, the operation of the 40φ extruder was stopped, a single layer sheet with a thickness of 2.0 mm consisting only of the resin for the main layer was extruded, and a nylon tufted sheet with a jute base fabric was heated on a cooling roll. The original carpet fabric was pasted. All of the extruded molten sheets were prone to film breakage or film peeling, and the sheets either lacked stable formability or were completely impossible to take off. When we measured the thread removal strength of the piles that somehow managed to be attached to the original carpet fabric, as shown in Table 1, the strength was less than 2 kg, and it was possible to easily pull out the pile by grasping it by hand. . Example 6 Evaflex was used instead of the resin for the main layer of Example 1.
A sound insulating carpet was prepared in exactly the same manner as in Example 1, except that a dry blend of 250, 15 parts and 85 parts of Carpet (a granulated product of 80 parts of calcium carbonate and 20 parts of resin manufactured by Nitto Funka Kogyo Co., Ltd.) was used. The moldability of the sheet was good, and the suture removal strength of the resulting sound-insulating carpet was 2.9 kg. Comparative Example 5 In Example 6, the operation of the 40φ extruder was stopped,
A single-layer sheet with a thickness of 2.0 mm consisting only of the resin for the main layer was extruded, but the molten sheet easily broke and was difficult to take off.

[Table] Example 7 A carpet with the following thickness and areal density was made in Example 1. Thickness Surface density (Kg/m ² ) Carpet 10 0.9 Secondary layer 0.2 0.2 Main layer 1.8 3.2 Iron plate 1 7.8 The sound insulation effect of this carpet was measured using JISA1416 (method for measuring sound transmission loss of sound insulation materials). As a result, we obtained the relationship shown in the figure. This value is superior to the theoretical value calculated from the thickness and surface density, and it is assumed that the carpet pile has a sound insulation effect.

[Brief explanation of drawings]

The drawing is a diagram showing the relationship between transmission loss and frequency of a carpet in which the present invention is implemented.

Claims (1)

[Claims] 1 Inorganic filler 65 to 95 using a T-die coextruder
% and a second thermoplastic synthetic resin containing 0 to 65% of an inorganic filler are coextruded into a sheet, and when the sheet is hot, the second thermoplastic synthetic resin is A method for producing a sound insulating carpet, which comprises rolling crimping the surface of a sheet made of plastic synthetic resin and the back surface of a carpet material. 2. The method for producing a sound insulating carpet according to claim 1, wherein polyethylene or ethylene copolymer is used as the thermoplastic synthetic resin. 3. Claim 2 in which an ethylene/vinyl ester copolymer or an ethylene/unsaturated carboxylic acid ester copolymer is used as the ethylene copolymer.
A method for producing a sound insulating carpet as described in Section 1. 4. The method for producing a sound insulating carpet according to claim 3, wherein an ethylene/vinyl acetate copolymer having a vinyl acetate content of 5 to 50% by weight is used as the ethylene/vinyl ester copolymer. 5. The method for producing a sound insulating carpet according to claim 1, wherein calcium carbonate or barium sulfate is used as the inorganic filler. 6. The method of manufacturing a sound insulating carpet according to claim 1, wherein an inorganic filler is prepared by pre-agglomerating inorganic powder into particles using a resin that is compatible with the thermoplastic synthetic resin as a coagulant.