TWI706004B - Thermoplastic polyurethane composition - Google Patents

Abstract

A thermoplastic polyurethane composition is used to solve the problem of the strength and water proof ability of a plastic product made by overmolding. The thermoplastic polyurethane composition consists of 91-99 wt% of a polyurethane and 1-9 wt% of a strengthen fiber. The polyurethane includes at least one hard polyurethane and at least one soft polyurethane.

Description

Thermoplastic polyurethane composition

The present invention relates to a thermoplastic polyurethane composition, especially a thermoplastic polyurethane composition used for injection molding and forming into parts.

In the industry, in order to enhance the beauty of plastic products or improve the mechanical properties (such as increasing strength, hardness, wear resistance, etc.), injection or coating can be used to form a primary product, and then injection Overmolding the primary product to form the final plastic product.

For example, when used for pull tab injection, you can first use soft thermoplastic polyurethane with a Shore hardness of 60-95A (hardness 60-95 Shore A) as the first plastic to form the primary product, and then use the Shore hardness as the same 60~95A soft thermoplastic polyurethane is used as a second plastic to be injected and covered to form the plastic product. At this time, the second plastic can have a different color from the first plastic to increase the aesthetics. And the plastic product is softer, but Due to its low hardness, its wear resistance is not good; or, after forming the primary product with a soft thermoplastic polyurethane with a Shore hardness of 60~95A as the first plastic, then using a Shore hardness of 50~74D (hardness Shore 50-74D) The second plastic is injected and covered to form the plastic product, which can increase the hardness of the plastic product; or, when making a waterproof slide fastener (slide fastener), you can first use a soft with a Shore hardness of 85A Thermoplastic polyurethane is used as the first plastic to be extruded to form the primary product (namely, tarpaulin tape). After perforating the tarpaulin tape, a rigid thermoplastic polyurethane with a Shore hardness of 50-74D is used as the primary product. The second plastic is injected and covered with molded scoops; however, the hardness and water resistance of the final plastic product obtained need to be improved.

In order to solve the above-mentioned problems, the object of the present invention is to provide a thermoplastic polyurethane composition which can be used in the injection molding process and can form a plastic product with good hardness, strength and water resistance.

The thermoplastic polyurethane composition of the present invention is composed of 91 to 99% by weight of thermoplastic polyurethane and 1 to 9% of reinforcing fibers. The thermoplastic polyurethane includes at least one rigid thermoplastic polyurethane and at least one soft thermoplastic polyurethane; wherein, The rigid thermoplastic polyurethane is 3070DU-W with a Shore hardness of 72D and/or 8102 with a Shore hardness of 74D, and the soft thermoplastic polyurethane is 3095AU with a Shore hardness of 93A.

Accordingly, the thermoplastic polyurethane composition of the present invention, through the combination ratio of the at least one rigid thermoplastic polyurethane, the at least one soft thermoplastic polyurethane, and the reinforcing fiber, enables the thermoplastic polyurethane composition to be used as the second plastic. The primary product formed with the first plastic is compounded into a part with better hardness and water resistance, so that the part is not easily damaged by external force, and the service life of the part can be improved.

In the thermoplastic polyurethane composition of the present invention, the reinforcing fiber is a glass fiber. In this way, when the thermoplastic polyurethane composition is combined with the primary product formed by the first plastic to form the part, the part can have better hardness, strength and water resistance.

The use of the thermoplastic polyurethane composition of the present invention is for injection molding to form a part of a part; for example, the part can be a pull tab, and the thermoplastic polyurethane composition is used to form a grip of the pull tab Alternatively, the part may be a waterproof zipper, and the thermoplastic polyurethane composition forms a chain tooth of the waterproof zipper. The part is formed by injection covering, which can be It is the effect of the present invention to enhance the beauty of the part, or to improve the mechanical properties of the part (such as increasing strength, hardness, wear resistance, etc.).

1: pull tab

11: Joint

12: Grip

2: Waterproof zipper

21: webbing

22: Waterproof layer

23: Sprocket

C: Clamping parts

F: Strength

H: Through hole

W: width

[Figure 1] A top view of a pull tab formed from the thermoplastic polyurethane composition of an embodiment of the present invention.

[Figure 2] A side cross-sectional view of the pull tab of Figure 1.

[Figure 3] A top view of a waterproof zipper formed from the thermoplastic polyurethane composition of an embodiment of the present invention.

[Figure 4] A cross-sectional side view of the waterproof slide fastener shown in Figure 3.

[Figure 5] A schematic diagram of the test method for testing the waterproof zipper shown in Figure 3.

In order to make the above and other objects, features and advantages of the present invention more comprehensible, the preferred embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings: "Polyurethane" and "soft thermoplastic polyurethane" refer to thermoplastic polyurethanes with different hardnesses. Among them, hard thermoplastic polyurethane has a higher hardness, and the hardness unit used can be Shore D (Shore D), while soft thermoplastic polyurethane has a lower hardness. The hardness unit used may be Shore A (Shore A), which can be understood by those with ordinary knowledge in the technical field of the present invention, and will not be repeated here.

The thermoplastic polyurethane composition of an embodiment of the present invention may include a thermoplastic polyurethane (thermoplastic polyurethane) and a reinforcing fiber, for example, may include 88 to 99% of the thermoplastic polyurethane and 1 to 12% of the reinforcing fiber by weight. By the thermoplastic The combination of polyurethane and the reinforcing fiber enables the thermoplastic polyurethane composition to be used as a second plastic to coat a primary product formed by a first plastic to be formed into a secondary product, and can be combined with the primary product to form a good One of the parts of hardness and water resistance, the part can be a pull tab 1 as shown in Figures 1 and 2, which includes a coupling part 11 and a gripping part 12, the gripping part 12 can be The thermoplastic polyurethane composition is formed; in addition, the part can also be a waterproof zipper 2 as shown in Figures 3 and 4, which includes a webbing 21, a waterproof layer 22, and a sprocket 23. The waterproof layer 22 covers The webbing 21 is covered to form a waterproof cloth belt, and after a plurality of through holes H are formed on the waterproof cloth belt, the sprocket 23 is formed, and the sprocket 23 may also be formed of the thermoplastic polyurethane composition.

In detail, the thermoplastic polyurethane may include at least one rigid thermoplastic polyurethane and at least one soft thermoplastic polyurethane. The at least one rigid thermoplastic polyurethane may refer to those having a Shore hardness of 60D or more, and the at least one soft thermoplastic polyurethane may refer to Shore hardness. The hardness is below 98A.

In this embodiment, the at least one rigid thermoplastic polyurethane may be 3070DU-W with a Shore hardness of 72D or 8102 with a Shore hardness of 74D, and the at least one soft thermoplastic polyurethane may be 3095AU with a Shore hardness of 93A. In addition, the mechanical properties of the aforementioned 3070DU-W, 8102 and 3095AU are shown in Tables 1 to 3.

In addition, the reinforcing fiber can improve the mechanical properties of the at least one soft thermoplastic polyurethane. Therefore, when forming the thermoplastic polyurethane composition, it is preferable to mix the at least one soft thermoplastic polyurethane with the reinforcing fiber first, and then continue to mix it. The at least one rigid thermoplastic polyurethane; or the at least one rigid thermoplastic polyurethane may be mixed with the reinforcing fiber first, and then the at least one soft thermoplastic polyurethane may be mixed. In this embodiment, a glass fiber may be selected as the reinforcing fiber , After first mixing with the at least one soft thermoplastic polyurethane, and then mixing with the at least one hard thermoplastic polyurethane.

In order to verify that when the thermoplastic polyurethane composition of the present embodiment and the primary product can be composited into the part, the part can have better hardness, strength and water resistance, 3085A (Shore hardness of 85±2A) is used as the part. After the first plastic is formed into the waterproof cloth tape (#10) and the through holes H are formed, the thermoplastic polyurethane composition shown in Table 4 is used as the second plastic to be injected and covered to form the sprocket 23 (# 10), and further form the waterproof zipper 2 of the A1~A6 group (as shown in Figure 5).

Next, as shown in Figure 5, on the day when the A1~A6 groups of waterproof zipper 2 are formed, a set of clamping members C clamps the waterproof cloth tape on both sides (the waterproof layer 22 covers the webbing 21) ), the clamping width W is about 1 inch, and the group of clamping pieces C is used to apply force F to both sides. By measuring the force F, the tensile strength (lateral tension ), the results show: group A1 is 11.56kgf/cm ² , group A2 is 31.34kgf/cm ² , group A3 is 71.52kgf/cm ² , group A4 is 89.71kgf/cm ² , group A5 is 88.09 kgf/cm ² , and the A6 group is 91.59 kgf/cm ² , among which the results of the tensile strength of the A4 to A6 groups waterproof zipper using the thermoplastic polyurethane composition of this embodiment are better.

In addition, the waterproofness of the waterproof zipper is related to the horizontal tension. When the measured horizontal tension is large, it shows that the sprocket formed by the second plastic and the waterproof cloth tape formed by the first plastic have a good bondability, and the water is not easy to free itself. The joint between the chain teeth and the waterproof cloth belt leaks. Therefore, when the thermoplastic polyurethane composition of this embodiment is used as the second plastic, it can be applied to form a waterproof zipper with better hardness and strength and waterproofness.

In summary, the thermoplastic polyurethane composition of the present invention uses the combination ratio of the at least one rigid thermoplastic polyurethane, the at least one soft thermoplastic polyurethane and the reinforcing fiber so that the thermoplastic polyurethane composition can be used as the second plastic , It can be combined with the primary product formed by the first plastic to form a part with better hardness, strength and water resistance, so that the part is not easily damaged by external force, and the service life of the part can be improved.

In addition, the use of the thermoplastic polyurethane composition of the present invention is to inject the coating into The shape is the part, so that the beauty of the part can be improved, or the mechanical properties of the part can be improved (such as increasing strength, hardness, wear resistance, etc.), which is the effect of the present invention.

Although the present invention has been disclosed using the above-mentioned preferred embodiments, it is not intended to limit the present invention. Anyone who is familiar with the art without departing from the spirit and scope of the present invention may make various changes and modifications relative to the above-mentioned embodiments. The technical scope of the invention is protected. Therefore, the scope of protection of the invention shall be subject to the scope of the attached patent application.

2: Waterproof zipper

21: webbing

22: Waterproof layer

23: Sprocket

H: Through hole

Claims (5)

A thermoplastic polyurethane composition is composed of 91 to 99% by weight of thermoplastic polyurethane and 1 to 9% of reinforcing fibers. The thermoplastic polyurethane includes at least one rigid thermoplastic polyurethane and at least one soft thermoplastic polyurethane; wherein, the rigid The thermoplastic polyurethane is 3070DU-W with a Shore hardness of 72D and/or 8102 with a Shore hardness of 74D, and the soft thermoplastic polyurethane is 3095AU with a Shore hardness of 93A. The thermoplastic polyurethane composition of claim 1, wherein the reinforcing fiber is a glass fiber. A use of the thermoplastic polyurethane composition of claim 1 or 2 for injection molding to form a part of a part. The use of the thermoplastic polyurethane composition of claim 3, wherein the part is a pull tab, and the thermoplastic polyurethane composition forms a grip portion of the pull tab. The use of the thermoplastic polyurethane composition of claim 3, wherein the part is a waterproof zipper, and the thermoplastic polyurethane composition forms an element of the waterproof zipper.

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