JPS629010B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method of manufacturing a sound insulating carpet for an automobile. 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 lined with low-density polyethylene are mainly used through lamination processing to smooth uneven car floors. They are press-molded to fit. Recently, with the aim of reducing the noise level inside cars and improving comfort,
There is a growing demand for carpets with excellent sound insulation performance. However, current automobile carpets do not have sufficient sound insulation performance because the laminated low-density polyethylene backing layer is only a few hundred micrometers thick. One possible solution to this problem is to thicken the backing layer of low-density polyethylene in order to increase the areal density and improve the sound insulation performance, but this method also increases the raw material cost and requires the carpet press. It was found that there were drawbacks such as a longer molding cycle and lower production speed, and a stiffer carpet that made it difficult to install. As a result of extensive research into the production of sound insulating carpets for automobiles, the present inventors discovered that ethylene-vinyl acetate copolymer (hereinafter referred to as
It consists of a one-step processing process in which a T-die sheet of EVA (also abbreviated as EVA) is formed and at the same time laminated to the back side of the carpet material while hot.It is inexpensive and has excellent sound insulation performance and press formability. Found a way to make carpets. Therefore, the present invention relates to a method for manufacturing a sound insulation carpet for an automobile, and the sound insulation carpet is manufactured using a vinyl acetate content of 5 to 30% by weight and a melt index of 0.1.
~400g/10min ethylene-vinyl acetate copolymer
20 to 70 parts by weight and compatible with the copolymer (1) wax, (2) attacking polypropylene, (3) ethylene-vinyl acetate copolymer having a melt index of about 30 or more, (4) ) rosin or rosin derivative, (5) terpene resin, (6) petroleum resin, or (7) asphalt as a coagulant;
Formulations containing inorganic fillers in high concentrations of more than 80%
This is carried out by extruding a mixture consisting of ~30 parts by weight into a sheet using a T-die extruder, and pressing the extruded sheet against the back side of a carpet original fabric while hot. However, carpet backing mixtures containing EVA, a certain type of resin that is compatible with EVA, and a high concentration of inorganic fillers are disclosed in, for example, Japanese Patent Publication Nos. 46-22191 and 46-31736. As already known from Japanese Patent Laid-Open Publication No. 48-51939, such a mixture is a low-viscosity mixture prepared by simultaneously blending and stirring the above-mentioned components. Even if this mixture is fed to an extruder equipped with a T-die, which is the object of the present invention, a surging phenomenon occurs in the extruder, making satisfactory extrusion molding impossible. Therefore, when such a low viscosity mixture is used, a roll coating method as described in, for example, Japanese Patent Publication No. 46-22191 is applied. However, if a resin that is compatible with EVA is used as a binder for the inorganic filler and is pre-coagulated, the inorganic filler, which originally has poor miscibility with EVA, can be simply dry blended with EVA, making it possible to A uniform molten sheet can be obtained simply by feeding the molten material from the molten resin into a T-die extruder used for carpet bagging polyethylene. This is due to the use of a resin component as a coagulant that has both compatibility with EVA and miscibility with inorganic fillers. The fact that bonding has become possible can be said to be extremely significant from an industrial perspective. In the present invention, EVA refers to a vinyl acetate content of 5 to 5.
30% by weight, melt index 0.1-400g/10
min, preferably a vinyl acetate content of 10 to 25% by weight and a melt index of 1 to 50 g/10 min. If EVA with a vinyl acetate content of less than 5% by weight is used, the carpet pile will have poor suction strength, bending strength, flexibility, cold resistance, and press formability.
Even if EVA has a vinyl acetate content of more than 30% by weight, it is not preferable because the heat resistance of the carpet will be poor. Furthermore, if EVA with a melt index of less than 0.1 g/10 minutes is used, the thread removal strength and press formability of the pile of the formable carpet of the T-die sheet will be poor, and the melt index will exceed 400 g/10 minutes.
Use of EVA is not preferable because it has poor bending strength, cold resistance, and heat resistance. Of course, in the present invention, for the purpose of improving flexibility and other qualities and reducing costs, two or more types of EVA with different vinyl acetate contents and melt indexes may be used together, or polyethylene, polypropylene, ethylene, etc. may be used as a third component.
It is also possible to add propylene copolymers, asphalt, etc. In the present invention, a compound containing a resin compatible with EVA as a coagulant and a high concentration of inorganic filler is an inorganic filler that is originally in the form of fine powder such as calcium carbonate, barium sulfate, talc, or silica. A compound containing at least 70% of It refers to a compound that can be easily extruded. A particularly preferred inorganic filler is calcium carbonate. Used as a binder in the above formulations
Components that are compatible with EVA include (1)
Waxes such as paraffin waxes, microcrystalline waxes, and polyethylene waxes, (2)
Attractive polypropylene, (3) ethylene-vinyl acetate copolymer with a melt index of about 30 or more, (4) rosin or rosin derivative, (5) terpene resin, (6) aliphatic, alicyclic, aromatic petroleum resins consisting of hydrocarbons or mixtures thereof;
(7) Asphalt is used, each of which may be used alone or as a mixture of two or more. These resin components normally have a negative effect on the physical properties of carpets such as bending strength and cold resistance, so the content of resin components in the compound should be kept as low as possible unless the pellets of the compound lose their shape during handling. It's better. A blend containing such a high concentration of an inorganic filler can be prepared using a melt kneading device such as a Banbury mixer, an intensive mixer, or a twin-screw extruder. For this purpose, a more excellent formulation can be obtained by using a resin component in the form of powder or granules. According to the invention, the mixing ratio of EVA and the formulation containing a high concentration of inorganic fillers is from 20 parts by weight to 80 parts by weight to 70 parts by weight to 30 parts by weight, preferably from 25 parts to 75 parts by weight. 45 parts by weight versus 55 parts by weight. If the amount of EVA blended is less than 20% by weight with respect to the mixed composition of EVA and inorganic filler blend,
Extrusion moldability, flexibility and mechanical properties of the molded product are poor, and if the content exceeds 70% by weight, the cost of raw materials becomes high and the density of the mixed composition consisting of EVA and an inorganic filler mixture is low. Therefore, in order to have sufficient sound insulation performance, it is necessary to thicken the packing layer of the carpet, which deteriorates the press formability of the carpet. In the method of the present invention, which has excellent blendability between each component in relation to the mixing ratio of the compound,
The mixing ratio of the compound containing EVA and a high concentration of inorganic filler can be changed as appropriate at the backing work site, and therefore a flexible or rigid sound-insulating carpet that meets the user's needs can be obtained at will. Very important practical advantages are also obtained. The process of lining carpets with a mixture of EVA and inorganic filler according to the present invention is as follows:
First, a dry blend of EVA and an inorganic filler mixture is extruded into a molten sheet several millimeters thick using a T-die extruder, after adding a softener such as a plasticizer if necessary. Before the molten sheet is cooled and solidified, it is bonded to the back side of the original carpet using a pressure roll. In this lamination process, it is possible to use the original carpet as it is, with the chute having only been subjected to a primary backing process using polypropylene as the first base fabric. It is also possible to use a raw carpet fabric which has been subjected to a secondary backing process with low density polyethylene by lamination process, such as carpet. In this lamination process, it is important to control the temperature of the extruded sheet and the spacing between the pressure rolls. By appropriately adjusting these, it is possible to create a backing with excellent pile removal strength and no deformation of the carpet pile. Can be processed. As described above, the present invention uses EVA as a carpet backing material and a mixture of an inorganic filler in the form of flakes, granules, or pellets using a resin component that is compatible with EVA as a binder.
By molding the extruded sheet with a die and simultaneously laminating it with the original carpet fabric while hot, it is inexpensive, has a backing layer with high areal density, has excellent pile removal strength, and can be used at low temperatures. This made it possible to manufacture sound insulating carpets for automobiles that can be press-formed. The present invention will be explained in more detail below with reference to Examples, but the present invention is not limited to these Examples. Example 1 Polyethylene wax (density 0.930, molecular weight
4000), 10 parts of attack polypropylene (density 0.87, molecular weight 30000), 0.2 parts of calcium stearate, and 80 parts of calcium carbonate, using a Banbury mixer on the high rotor speed side.
70min ^-1 , low speed side 65min ^-1 , temperature 125℃, kneading time
After melt mixing under conditions of 10 minutes, the molten mixture was pelletized by discharging through an extruder to obtain a pelletized high concentration calcium carbonate formulation. Next, a mixture obtained by dry blending 35 parts of Evaflex P1907 (manufactured by Mitsui Polychemical Co., Ltd., vinyl acetate content 19% by weight, melt index 15 g/10 minutes) and 65 parts of the above calcium carbonate blend was mixed into a 700 mm wide Using a 65mm extruder (L/D=24) equipped with a T-die, the cylinder temperature was 160℃,
Screw rotation speed 50min ^-1 , T die temperature 150~155
℃, a die lip of 15 mm, and a line speed of 0.7 m/min to form a sheet of calcium carbonate-containing EVA with a width of 650 mm, a thickness of 2.0 mm, and a basis weight of 2.5 Kg/ ^cm3 . A sound insulating carpet for an automobile was lined by bonding the above-mentioned sheet to the carpet material (nylon pile first base fabric jute) fed from below the die using a pressure roll. Measurement results of the tensile properties (in accordance with ASTM D-882), low-temperature embrittlement temperature (in accordance with ASTM D-746), bicut softening point (in accordance with ASTM D-1525) of the single sheet that constitutes the backing layer of the created carpet, and the results of the carpet. Pile pull-out strength (23℃, tensile speed 200mm/
The measurement results of min) are shown in Table 1. Example 2, Comparative Example 1 Carpet lining was carried out in the same manner as in Example 1, except that the blending ratio of Everflex P1907 and calcium carbonate was changed. The evaluation results are shown in Table 1. Examples 3-4, Comparative Examples 2-3 Carpet lining was carried out in the same manner as in Example 1, except that Evaflex shown in Table 2 was used instead of Evaflex P1907. The evaluation results are shown in Table 2. Examples 5-6 In Example 1, polyethylene wax (density 0.930, molecular weight
4000) and 10 parts of attack polypropylene (density 0.87, molecular weight 30000), alicyclic petroleum resin with a softening point of 100°C (Example 5)
or 20 each of aromatic petroleum resin (Example 6)
The carpet backing process was carried out exactly as in Example 1, except that a formulation consisting of 0.2 parts of calcium stearate and 80 parts of calcium carbonate was used. The evaluation results are shown in Table 3. Examples 7 and 8 Carpets were made in exactly the same manner as in Example 1, except that talc was used instead of calcium carbonate as the inorganic filler, and Evaflex of the brand shown in Table 4 was used as Evaflex. The lining process was carried out. The evaluation results are shown in Table 4.

【table】

【table】

【table】

[Table] Comparative Example 4 A mixture obtained by dry blending the respective components used in Example 1, namely, polyethylene wax 6.5 parts Attractive polypropylene 6.5 Calcium stearate 0.13 Calcium carbonate 52 Everflex P1907 35 A sheet was formed in the same manner as above. However, since it contains a large amount of calcium carbonate, kneading is insufficient, resulting in film breakage of the sheet, making it impossible to obtain a satisfactory sheet that can be used for carpet backing. Examples 9-13 In Example 1, a molten mixture consisting of 13 parts by weight of the following various coagulants, 0.2 parts by weight of calcium stearate and 52 parts by weight of calcium carbonate was used. [Example 9] Rosin ester system, ring and ball softening point
100℃: Arakawa Chemical Products Super Ester 100) [Example 10] Terpene (terpene polymer, ring and ball softening point 100℃: cheap crude oil product YS Resin PX-1000) [Example 11] Asphalt (penetration 60/80 : Shell Petrochemicals) [Example 12] Attack polypropylene (Sumitomo Chemicals SK-11) [Example 13] Polyethylene wax (molecular weight
2000, melting point 110°C: Mitsui Petrochemicals Hiwax 220P) The evaluation of the backed carpet is shown in Table 5 below.

【table】

Claims (1)

[Claims] 1. Compatible with an ethylene-vinyl acetate copolymer having a vinyl acetate content of 5 to 30% by weight, a melt index of 0.1 to 400 g/10 minutes, and 20 to 70 parts by weight, and the copolymer. (1) wax, (2) attack polypropylene, (3) ethylene-vinyl acetate copolymer with a melt index of about 30 or higher, (4) rosin or rosin derivative, (5) terpene resin, (6) petroleum A mixture consisting of 80 to 30 parts by weight of a compound containing at least one of resin or (7) asphalt as a coagulant and an inorganic filler at a high concentration of about 70% or more is extruded into a sheet using a T-die extruder. 1. A method for producing a sound insulating carpet for an automobile, which comprises rolling-pressing an extruded sheet to the back side of a carpet material while hot. 2. The method for producing a sound insulating carpet according to claim 1, wherein the inorganic filler is calcium carbonate.