JP3215922B2 - Thermoplastic polyurethane resin composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermoplastic polyurethane resin composition, and more particularly to a thermoplastic polyurethane resin composition.
Film or sheet formability can be improved.
Composition that can be cut .

[0002]

2. Description of the Related Art Conventionally, thermoplastic polyurethane resins have been used as various molded products such as injection molded products, extrusion molded products, blow molded products and the like. However, it has been difficult to mold a thermoplastic polyurethane resin alone into a film or sheet due to its high tackiness due to the problem of blocking. For this reason, the thermoplastic polyurethane resin film or sheet is usually formed by casting on a carrier sheet such as release paper laminated with polyethylene, polypropylene or the like. Therefore, it is uneconomical, such as an increase in the carrier sheet peeling step and waste of the carrier sheet after peeling. In addition, in the film forming by the inflation method, since a large amount of an inorganic filler is mixed in the resin to form the resin, the characteristics of the thermoplastic polyurethane resin are impaired, and there is also an uneconomical problem due to the addition of the inorganic filler . Further, since the thermoplastic polyurethane resin has a low melt tension and a large temperature dependency, the range of conditions for film formation is narrow. For this reason, there is also a problem that the film is not stable in film formation and it is difficult to reduce the film thickness. As a resin composition for improving the moldability of such a thermoplastic polyurethane resin film, for example, a composition comprising a soluble and / or thermoplastic polyurethane obtained by mixing a thermoplastic polyurethane with a specific ethylene copolymer (Japanese Patent Application Laid-Open No. 50-76165), and a resin composition containing a thermoplastic urethane elastomer and an acid-containing thermoplastic olefin- based copolymer having an acid value of 2 to 100 (JP-A-61-271351). However, although the conventional thermoplastic polyurethane resin composition has been found to have an improved effect of suppressing film blocking and improving film formability, it is not always sufficient and has room for improvement.

[0003]

DISCLOSURE OF THE INVENTION The present invention relates to a film capable of suppressing film blocking without impairing the properties of a thermoplastic polyurethane resin, and stably forming a thin film and increasing the speed of molding. An object of the present invention is to provide a resin composition having improved moldability.

[0004]

The present invention has been found to achieve the above object by blending a thermoplastic polyurethane resin with a polyethylene resin and an ethylene-propylene copolymer rubber in combination. That is, the present invention provides that (a) 35 to 90% by weight of a thermoplastic polyurethane resin, (b) 5 to 60% by weight of a polyethylene resin, and (c) 5 to 40% by weight of an ethylene-propylene copolymer rubber. Characteristic thermoplastic polyurethane
Improve the formability of film or sheet with resin
The gist of the present invention is a thermoplastic polyurethane resin composition capable of: Further, the present invention relates to (a) a thermoplastic polyurethane resin 3
5-90 wt%, (b) port Riechiren resin 5-60 wt
% And (c) an ethylene-propylene copolymer rubber 5 to 5%.
Thermoplastic polyurethane resin composition comprising 40% by weight
Summary of polyurethane film characterized by consisting of
And

Hereinafter, the present invention will be described in detail. The (a) thermoplastic polyurethane resin in the present invention includes:
Polyurethane elastomers of adipate type, polyether type, polycaprolactone type, polyester type and the like can be mentioned. Of these, adipate-based and polycarbonate-based ones are preferred from the viewpoint of compatibility with the polyethylene resin . Such a thermoplastic polyurethane elastomer preferably has a JISA hardness of about 80 to 100 or a softening point of about 90 to 140 ° C.

[0006] The polyethylene resin (b) in the present invention includes a homopolymer of ethylene . Polyethy
Specific examples of the ren resin include low density polyethylene and high density
Polyethylene and the like . The melt index (MI, 190 ° C.,
The load of 2.16 kg) is preferably 0.05 to 20 g / 10 min, more preferably 0.1 to 0.6 g / 10 min .
You.

In the present invention, the ethylene-propylene copolymer rubber (c) includes ethylene-propylene copolymer rubber (EPR) and ethylene-propylene diene copolymer rubber obtained by copolymerizing a diene compound with the rubber (EPR). E
PDM). The ethylene-propylene copolymer rubber preferably has an ethylene content of 50 to 90 mol% and a propylene content of 50 to 10 mol%. More preferable ranges are 70 to 80 mol% of ethylene and 30 to 20 mol% of propylene. In the case of ethylene-propylene diene copolymer rubber (EPDM), examples of the diene compound include ethylidene norbornene, dicyclopentadiene, and 1,4-hexadiene. Among such ethylene-propylene copolymer rubbers, ethylene-propylene diene copolymer rubber (EPDM) is preferable. Melt flow rate of ethylene-propylene copolymer rubber (MI, 190
C, 2.16 kg load) is preferably from 0.1 to 5.0 g / 10 min, more preferably from 0.3 to 1.0 g / 10 min.

Next, the mixing ratio of each component in the thermoplastic polyurethane resin composition is as follows: (a) 35 to 90% by weight, preferably 45 to 80% by weight of the thermoplastic polyurethane resin, and (b) 5 to 90% by weight of the polyethylene resin. 60% by weight, preferably 10 to 40% by weight, and (c) 5 to 40% by weight, preferably 10 to 2% by weight of the ethylene-propylene copolymer rubber.
0% by weight. When the thermoplastic polyurethane resin is 35
When the amount is less than the weight percentage, the properties of the polyurethane elastomer are lost, and the abrasion resistance and mechanical strength, which are the properties of the polyurethane, are reduced. On the other hand, if the content exceeds 90% by weight, there are problems such as occurrence of blocking in film production and lack of film production stability. If the content of the polyethylene resin is less than 5% by weight, blocking occurs in the film formation. On the other hand, if the content exceeds 60% by weight, the properties of the polyurethane elastomer are impaired, and the abrasion resistance and mechanical strength, which are the properties of the polyurethane, are also reduced. Further, if the ethylene-propylene copolymer-based rubber is less than 5% by weight, the application of melt tension is insufficient and the stability in film formation of the film is insufficient, while if it exceeds 40% by weight, blocking occurs. In addition, abrasion resistance and mechanical strength, which are characteristics of polyurethane, decrease. In the present invention, in addition to the above components, an antioxidant, an ultraviolet absorber, a coloring agent, an inorganic filler, and the like can be appropriately compounded. The thermoplastic polyurethane resin composition of the present invention may contain , for example, Hensche , by adding each of the above resin components and other components as necessary.
Rumikisa or were dry blended in advance using a high speed mixer, obtained by pelletizing extruded and melt-kneaded with heating under, for example, an extruder or the like at about 180 to 220 ° C.,. Next, a method for producing a film from this thermoplastic polyurethane resin composition is usually
It is a known method of forming a poly olefin film T
-Flat film or inflation by die extruder
Can be shaped as Chiyubu shaped film by Shon method, it is possible to perform stretching and vertical and horizontal balance in one step, and cooling that can fast molding a thin film
The inflation method is preferred in terms of productivity. The thickness of the film is usually formed in the range of about 10 to 100 μm. Above, in inflation molding by air-cooling method, a resin temperature of 180 to 220 ° C., a blow-up ratio 2.0
It is preferable to carry out in the range of 5.0. This gives a thickness of 10
の も の 100 μm is obtained.

[0009]

The composition obtained by blending polyethylene with a thermoplastic polyurethane resin has improved melt tension as compared with a thermoplastic polyurethane resin alone. This is considered to be due to the melt tension of polyethylene. However, the melt tension of polyethylene greatly depends on the temperature, and when the temperature is increased, the decrease is remarkably observed. The composition comprising the thermoplastic polyurethane resin, the polyethylene resin and the ethylene-propylene copolymer rubber of the present invention has a small temperature dependency and a small decrease in the melt tension even at a relatively high temperature. Therefore, stable thermoforming can be performed without greatly impairing the characteristics of the thermoplastic polyurethane resin.
Film forming, especially air-cooled inflation
In the alternative method, bubbles necessary for thinning and speeding up of molding are stabilized. Further, the blocking property can be reduced without impairing the properties of the thermoplastic polyurethane resin.

[0010]

The present invention will be described in more detail with reference to the following examples. The following resin was used as a raw material. (1) Thermoplastic polyurethane resin PU-1: (density 1.19 g / cm ³ , softening point 120 ° C, adipate type) PU-2: (density 1.11 g / cm ³ , softening point 97 ° C, ether type) ( 2) Ethylene-propylene copolymer rubber EPDM: (Propylene content 27% by weight, iodine value 12, Mooney viscosity (120 ° C.) 50) (3) Polyethylene resin low density polyethylene (LDPE): (density 0.923 g / cm ^3, MI0.8 g / 10 min) high-density polyethylene (HDPE) :( density ^{0.955g / cm 3, MI0.5 g /} 10 min) example 1-4. Comparative Examples 1-4. At the mixing ratio shown in Table 1, a thermoplastic polyurethane resin, Po
Riechiren resin and an ethylene-propylene copolymer rubber were dry blended in a super mixer, Paix then charged into an extruder, kneaded to the composition at a resin temperature of 200 ° C.
Got a let . Further, air cooling method inflation each component of the
The film was supplied to an extruder of a thin film forming apparatus to form a film under the film forming conditions shown in Table 1. Table 1 shows the melt tension of each composition, the moldability of each film, and the physical properties of each film. In addition, the test method in an Example and a comparative example is as follows. (1) Melt tension: Using a “melt tension tester” manufactured by Toyo Seiki Co., Ltd., extrusion speed: 10 mm / min. ,
Tensile speed: 1 mm / min. , Capillary length: 8m
m, capillary diameter: 2.095 mm, barrel diameter:
It measured on the conditions of 9.55 mm and temperature: 190 degreeC. (2) Bubble stability: Bubble during film formation of the inflation film was observed, and a stable one was indicated by ○ , an unstable one was indicated by Δ, and an unstable one that was difficult to form a film was indicated by X. (3) Blow ratio: The maximum blow ratio at which film formation was possible. (4) High-speed film-forming property: The film-forming rate was increased under a constant condition of the extrusion rate and the blow ratio of the molten resin, and the value was expressed as a minimum film thickness (μ) at which film formation was impossible. (5) Blocking resistance: the Chiyubu like film nipping <br/>, to observe the degree of blocking when wound by peeling off the two films by cutting both ends, those peeling of the film is prepared ○ , a film having slight blocking was indicated by △, and a film in which the film was not peeled off by blocking was indicated by X. (6) breaking strength: JISL over 1096 (7) elongation at break: JISL over 1096 (8) after 50% elongation strain: JISL over 1096 (9) Thermal shrinkage: 80 ° C., 7 days after the shrinkage area% Indicated by (10) Film surface resistance: to observe the surface of the film, ○ a favorable, what little rough △, showing what rough skin in X.

[0011]

[Table 1]

[0012]

[Table 2]

[0013]

As described in detail above, the thermoplastic polyurethane resin composition of the present invention has a lower temperature dependency of the melt tension than the thermoplastic polyurethane resin or the polyethylene resin- blended composition, and the thermoforming molding. Excellent in nature. Particularly, in the molding of a film by the air-cooled inflation method, since the molding of the bubble is stable, it is possible to reduce the thickness of the thermoplastic polyurethane resin film and improve the high-speed moldability.
In addition, since the film or sheet has improved blocking resistance, it can be handled alone without using a carrier sheet such as release paper in the formation of the film or sheet . There are also effects such as simplification, improvement in handleability, and reduction in manufacturing cost. Therefore, it can be used for various molded articles, but is particularly suitable as a resin composition for forming a film or a sheet.

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-58-164629 (JP, A) JP-A-2-160869 (JP, A) JP-A-50-138045 (JP, A) JP-A 50-164629 76165 (JP, A) JP-A-61-271351 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C08L 75/00-75/16 C08L 23/00-23/36 C08J 5/18

Claims (2)

(57) [Claims] (1) a thermoplastic polyurethane resin 35 to 9
Thermoplastic polyurethane comprising: 0% by weight, (b) 5 to 60% by weight of a polyethylene resin, and (c) 5 to 40% by weight of an ethylene-propylene copolymer rubber.
Improve the formability of film or sheet with resin
And a thermoplastic polyurethane resin composition. (A) thermoplastic polyurethane resin 35 to 9
A polyurethane film comprising a thermoplastic polyurethane resin composition comprising 0% by weight, (b) 5 to 60% by weight of a polyethylene resin, and (c) 5 to 40% by weight of an ethylene-propylene copolymer rubber.