阅读说明：本技术 一种有机硅改性tpu的组合物及其制备方法 (Organic silicon modified TPU composition and preparation method thereof ) 是由 李亚兵 杨小青 邹松 于 2021-06-29 设计创作，主要内容包括：本发明公开了一种有机硅改性TPU组合物及其制备方法,所述改性TPU组合物为在引发剂的引发下,反应型羟基有机硅改性剂与TPU发生交联反应的产物。该改性TPU组合物的制备方法包括S1：获取TPU；S2：在惰性气氛保护下,向熔融态的TPU内加入反应型羟基有机硅改性剂,混合过程中持续搅拌直到NCO达到理论值,即得到反应型羟基有机硅改性的TPU；S3：将步骤S2制得的反应型羟基有机硅改性的TPU与引发剂混合发生交联反应,得到所述的有机硅改性TPU组合物。通过反应型羟基有机硅改性剂改性TPU,使其成膜后硅氧烷基酯在TPU表面富集,可显著增强TPU表面的特性：润滑性、脱模性、耐磨性、斥水性、防污性,从而降低了TPU表面的粘黏性,增加了可加工性能。(The invention discloses an organic silicon modified TPU composition and a preparation method thereof, wherein the modified TPU composition is a product of a cross-linking reaction between a reactive hydroxyl organic silicon modifier and TPU under the initiation of an initiator. The preparation method of the modified TPU composition comprises the following steps of S1: obtaining a TPU; s2: under the protection of inert atmosphere, adding a reactive hydroxyl organic silicon modifier into the molten TPU, and continuously stirring in the mixing process until NCO reaches a theoretical value to obtain the reactive hydroxyl organic silicon modified TPU; s3: and (4) mixing the reactive hydroxyl organic silicon modified TPU prepared in the step S2 with an initiator to perform a crosslinking reaction to obtain the organic silicon modified TPU composition. The TPU is modified by the reactive hydroxyl organic silicon modifier, so that siloxane alkyl ester is enriched on the surface of the TPU after the TPU is formed into a film, and the surface characteristics of the TPU can be obviously enhanced: lubricity, mold release property, wear resistance, water repellency and antifouling property, thereby reducing the viscosity of the surface of the TPU and increasing the processability.)

1. The composition of the organic silicon modified TPU is characterized in that the composition is a product of a cross-linking reaction between a reactive hydroxyl organic silicon modifier and the TPU under the initiation of an initiator; wherein the composition has the structure:

2. the composition of the silicone-modified TPU of claim 1 wherein the raw materials for the composition comprise, in parts by weight:

3. the composition of the silicone-modified TPU of claim 2 wherein the raw materials for the composition comprise, in parts by weight:

4. the composition of the silicone modified TPU of claims 1-3 where the reactive hydroxysilicone modifier is a single-ended bishydroxy polydimethylsiloxanyl ester.

5. The composition of silicone modified TPU of claims 1-3 wherein said reactive hydroxysilicone modifier has a hydroxyl number of from 8 to 310mgKOH/g and a molecular weight of 340-.

6. The composition of the silicone-modified TPU of claim 2 or 3 wherein the isocyanate is diphenylmethane diisocyanate.

7. The composition of the silicone modified TPU of claims 2 or 3 wherein the initiator is an organic peroxide initiator.

8. A method of making the composition of the silicone modified TPU of any of claims 1 to 7 comprising the steps of:

s1: obtaining a TPU;

s2: under the protection of inert atmosphere, adding a reactive hydroxyl organic silicon modifier into the molten TPU, and continuously stirring in the mixing process until NCO reaches a theoretical value to obtain the reactive hydroxyl organic silicon modified TPU;

s3: and (4) mixing the reactive hydroxyl organic silicon modified TPU prepared in the step S2 with an initiator to perform a crosslinking reaction to obtain the organic silicon modified TPU composition.

9. The method of making the composition of silicone-modified TPU of claim 9, where step S1: the TPU is prepared by the process of high temperature melt polymerization, wherein an excess of isocyanate is maintained.

10. The process for preparing a composition of silicone modified TPU as set forth in claim 9 wherein step S1 specifically is: heating isocyanate to 80-90 ℃, heating polyester polyol or polyether polyol to 180-250 ℃, heating 1.4 Butanediol (BDO) to 100-250 ℃, adding the three heated raw materials into a dynamic mixer or a static mixer according to the formula requirements for rapid mixing, adding the mixed materials into a double-screw granulation system for reaction, extrusion and granulation, thereby preparing the polyurethane.

Technical Field

The invention belongs to the technical field of TPU (thermoplastic polyurethane) protective films, and particularly relates to an organic silicon modified TPU composition and a preparation method thereof.

Background

In recent years, with the development of society and the progress of technology, new materials are more and more widely applied, thermoplastic polyurethane elastomers (TPU) are changed from military use to dual-purpose use for military and civil use since the beginning of the last 80 th century, and mainly for civil use, the variety brands of products are continuously increased, the production scale is gradually enlarged, and the thermoplastic polyurethane elastomers play an important role in various departments of national economy and various aspects of clothes and eating habits of people.

Since TPU has the characteristics of softness, high strength and the like, TPU is gradually used in the fields of airplane floors, electronic component coating, airplane sealing, anticorrosion envelopes and the like to protect base materials and block external environment corrosion factors such as water vapor and the like, for example, 3M company in the united states uses a large amount of TPU protective films between airplane cabins and cargo holds and electronic devices to block water vapor and the like from entering airplane electronic devices. However, with the weight reduction of the airplane and the addition of more precise electronic instruments, the requirements of the market on the weather resistance and the barrier property of the traditional TPU film are higher and higher, so that the electronic devices can be protected by the barrier by using thinner TPU.

Meanwhile, along with the miniaturization of electronic devices, the hardness of the TPU must be reduced in order to enable the TPU to be better attached to the electronic devices, however, the processing difficulty of TPU products, particularly film products, must be increased after the hardness of the traditional TPU is reduced, and the main reason is that when the TPU film is extruded, the TPU temperature is high, the crystallization temperature of soft TPU is low, the shaping is slow, and the TPU film is bound together when being rolled. However, the precipitated wax often damages precise electronic components, such as slow heat dissipation caused by entering the electronic components. Therefore, there is a need to develop a soft TPU that is resistant to blocking after forming a film, does not cause damage to electronic components, and has high weather resistance and high barrier properties.

Disclosure of Invention

Aiming at the problems, the invention provides an organic silicon modified TPU composition and a preparation method thereof, wherein a reactive hydroxyl organic silicon modifier is used for modifying TPU, so that siloxane alkyl ester is enriched on the surface of TPU after film forming, and the surface characteristics of TPU can be obviously enhanced: lubricity, releasability, abrasion resistance, hydrophobicity, antifouling property, thereby reducing tackiness of the surface of TPU and improving workability.

In order to achieve the purpose, the technical scheme of the invention is as follows:

an organosilicon modified TPU composition is mainly aimed at thermoplastic elastomer polyurethane, and the composition is a product of a cross-linking reaction between a reactive hydroxyl organosilicon modifier and TPU under the initiation of an initiator; wherein the composition has the structure:

preferably, the raw materials of the composition comprise, in parts by weight:

the raw materials of the composition further comprise the following components in parts by weight:

preferably, the reactive hydroxysilicone modifier is of the single-ended bishydroxypolydimethylsiloxane series.

Preferably, the hydroxyl value of the reactive hydroxyl organic silicon modifier is 8-310mgKOH/g, and the molecular weight is 340-12000.

Preferably, the polyisocyanate is diphenylmethane diisocyanate.

Preferably, the initiator is an organic peroxide initiator, and the organic peroxide initiator refers to a compound containing peroxy groups (-O-), and the-O-bond is broken by heating and is split into two corresponding free radicals, so that the polymerization of the monomer is initiated, and the crosslinking and curing are realized, and the compound is preferably ammonium persulfate.

The invention also provides a preparation method of the organic silicon modified TPU composition, which comprises the following steps:

s1: obtaining a TPU;

s2: under the protection of inert atmosphere, adding a reactive hydroxyl organic silicon modifier into the molten TPU, and continuously stirring in the mixing process until NCO reaches a theoretical value to obtain the reactive hydroxyl organic silicon modified TPU; NCO is isocyanate group and is an important index for the quality of polyurethane products with a certain quantity;

s3: and (4) mixing the reactive hydroxyl organic silicon modified TPU prepared in the step S2 with an initiator to perform a crosslinking reaction to obtain the organic silicon modified TPU composition.

Preferably, the step S1: preparing TPU by a high-temperature melt polymerization process according to the weight parts of the components given above, wherein an excess of isocyanate is maintained;

the preparation method of the TPU specifically comprises the following steps:

heating isocyanate to 80-90 ℃, heating polyester polyol or polyether polyol to 180-250 ℃, heating 1.4 Butanediol (BDO) to 100-250 ℃, adding the three heated raw materials into a dynamic mixer or a static mixer according to the formula requirements for rapid mixing, adding the mixed materials into a double-screw granulation system for reaction, extrusion and granulation, thereby preparing the polyurethane.

Due to the adoption of the technical scheme, compared with the prior art, the invention has the following advantages and positive effects:

the invention modifies TPU through a reactive hydroxyl organic silicon modifier to obtain the TPU with an organic silicon group, namely, the organic silicon group is introduced into a chain segment of a polyurethane molecule, and the chain segment containing the organic silicon is incompatible with a TPU main body and gradually migrates to the surface of the TPU to form an organic silicon layer. In addition, the molecular weight of the TPU is usually very high (MW is more than 10 ten thousand), which causes poor melt flowability of the TPU and difficult processing, so that the TPU with the introduced organosilicon group reduces the molecular weight of the TPU, and is beneficial to improving the performances.

The invention introduces a group which is easy to process (lubricity), water vapor barrier (water repellency) and crosslinkable at the chain end of a polyurethane molecule, and the polyurethane can be aliphatic polyurethane or aromatic polyurethane. The molecular weight of the polyurethane need not be controlled and the polymerization is carried out according to the typical molecular weight values of polyurethanes (MW greater than 10 ten thousand) while incorporating an organic peroxide initiator. When the polyurethane composition is processed, the initiator can initiate the crosslinking groups to crosslink under the action of high temperature. The easy-to-process (lubricating), water vapor barrier (water repellent) and crosslinkable groups of the present invention are preferably single-ended bishydroxy polydimethylsiloxanyl ester groups, which enrich the surface of the polyurethane film after film formation. The surface characteristics (lubrication, water repellency, and stain resistance) of the polyurethane film are significantly enhanced, thereby improving the workability.

Detailed Description

The composition of an organosilicon modified TPU and the preparation method thereof proposed by the present invention are further described in detail with reference to the following specific examples. The advantages and features of the present invention will become more apparent from the following description.

An organic silicon modified TPU composition mainly aims at a thermoplastic elastomer TPU, the composition is a product of a cross-linking reaction between a reactive hydroxyl organic silicon modifier and the TPU under the initiation of an initiator, and the TPU can be aliphatic polyurethane or aromatic polyurethane; wherein the composition has the structure:

the composition comprises reactive hydroxyl organic silicon modified polyurethane and an organic hydrogen peroxide initiator, wherein the reactive hydroxyl organic silicon modified polyurethane is a polyurethane composition obtained by introducing single-ended dihydroxy polydimethylsiloxanyl ester groups into the end of a polyurethane molecular chain, and simultaneously mixing the reactive hydroxyl organic silicon modified polyurethane with the organic hydrogen peroxide initiator, the initiator can initiate the single-ended dihydroxy polydimethylsiloxanyl ester crosslinking groups to crosslink under the action of high temperature, and the siloxanyl ester is enriched on the surface of a polyurethane film after film formation, so that a polyurethane product which is easy to process, excellent in weather resistance and excellent in water vapor barrier property is prepared.

The TPU composition mainly comprises TPU preparation raw materials, a reactive hydroxyl organic silicon modifier and an initiator, and specifically comprises the following components in parts by weight:

further comprising:

the present invention also provides a process for preparing the above modified TPU composition comprising:

s1: preparing TPU by adopting a typical high-temperature melt polymerization preparation method of polyurethane according to the components, which comprises the following steps:

heating diphenylmethane diisocyanate (MDI) to 80-90 ℃ (preferably 80 ℃), heating polyester polyol or polyether polyol to 180-.

S2: under the protection of inert atmosphere, adding a reactive hydroxyl organic silicon modifier into the molten TPU, and continuously stirring in the mixing process until NCO reaches a theoretical value to obtain the reactive hydroxyl organic silicon modified TPU; NCO is an isocyanate group and is an important index for the quality of a quantitative polyurethane product.

S3: and (4) mixing the reactive hydroxyl organic silicon modified TPU prepared in the step S2 with an initiator to perform a crosslinking reaction to obtain the organic silicon modified TPU composition.

The performance test method of the sample prepared in the embodiment of the invention is as follows:

(1) easy processability evaluation: and flatly paving the modified TPU in a stainless steel tray, and putting the stainless steel tray into a preset oven at 200 ℃ for 15-20 min. Then, the sample was left at room temperature for 30min for evaluation: wherein 80-100% of the stainless steel tray is peeled off without adhesive, 50-80% of the stainless steel tray is peeled off with a small amount of adhesive, less than 50% of the stainless steel tray is peeled off with poor adhesive.

(2) And (3) testing the glossiness: the addition of the reactive hydroxyl organic silicon modifier can reduce the friction between the polyurethane material and a machine in the processing process, thereby increasing the glossiness of the polyurethane film according to the test of GB/T8807-1988 standard.

(3) Water vapor transmission rate: according to the GB/T21529-2008 test standard, the temperature is set to be 38 ℃, and the humidity is set to be 90% RH.

(4) Oxygen transmission rate: testing was performed according to ASTM D3985-2005 test standard.

The properties of the modified TPUs according to the invention are illustrated in detail in the following examples. All polyurethane samples were processed to polyurethane at temperatures above 90 ℃ by plastic processing means such as extrusion and injection molding to produce the desired articles.

1. Modified aromatic polyurethanes

Example 1:

(1) preparation of aromatic polyether urethane

Heating diphenylmethane diisocyanate (MDI) at the temperature of 80 ℃, heating polyether polyol to 250 ℃ of 180-.

(2) Preparation of polyurethane blocked with single-ended bishydroxy polydimethylsiloxanyl ester: and (2) heating the aromatic polyurethane polyether polyurethane prepared in the step (1) to a molten state under the protection of nitrogen, adding the single-ended dihydroxy polydimethyl siloxane alkyl ester into the polyurethane under the condition of stirring and mixing, and continuously stirring until the detected NCO reaches a theoretical value, thereby preparing the polyurethane blocked by the single-ended dihydroxy polydimethyl siloxane alkyl ester.

(3) And (3) mixing the polyurethane terminated by the single-ended dihydroxy polydimethyl siloxane alkyl ester prepared in the step (2) with an initiator ammonium persulfate to carry out a crosslinking reaction, thereby preparing the aromatic polyether type polyurethane composition terminated by the single-ended dihydroxy polydimethyl siloxane alkyl ester.

The preparation method of example 2 was the same as that of example 1, the preparation methods of comparative examples 1 and 2 were the same, neither step (3) was used, and comparative example 3 prepared only an aromatic polyether type TPU. Table 1 shows the compositions (in parts by weight) of the respective components of the above examples 1 to 2 and comparative examples 1 to 3.

TABLE 1

Components	Example 1	Example 2	Comparative example 1	Comparative example 2	Comparative example 3
						MDI	25.75	25.75	25.75	25.75	25.75
PTMEG1000	54.82	54.82	54.82	54.82	54.82
						BDO	5.2	5.8	5.8	5.2	6.35
SP-SI3200	10	2	2	10	0
						DTBP	6	2	0	0	0

MDI: diphenylmethane diisocyanate; wanhua chemistry;

PTMEG 1000: polytetramethylene ether glycol molecular weight 1000; basf chemistry;

BDO: 1, 4-butanediol;

SP-SI 3200: a single-ended bishydroxy polydimethylsiloxanyl ester having an OH number of 9mgKOH/g and a molecular weight of 3200/1600OH gram equivalents; jidi chemical;

DTBP: di-tert-butyl peroxide industrial grade high temperature initiator; aster chemistry

The TPU samples from the above examples and comparative examples were tested according to the TPU performance test method and the results are shown in table 2:

TABLE 2

As can be seen from Table 2, the aromatic polyether urethane composition obtained by adding the crosslinkable SP-SI3200 group at the chain end of the TPU molecular chain and simultaneously mixing the initiator has the advantages of obviously improved processability, abrasion resistance, tensile strength and glossiness, and obviously reduced water vapor transmission rate and oxygen transmission rate. This is mainly because the silicone is enriched on the surface after film formation, resulting in significant enhancement of film lubricity, mold release property, abrasion resistance, water repellency, and the like.

2. Modification of aromatic polyester urethanes

Example 3

(1) Preparation of aromatic polyester urethane: heating diphenylmethane diisocyanate (MDI) at the temperature of 80 ℃, heating polyester polyol to the temperature of 180-fold (preferably 180 ℃), heating 1.4 Butanediol (BDO) to the temperature of 100-fold (preferably 100 ℃), adding the three materials into a dynamic mixer or a static mixer for rapid mixing through a metering system according to the formula requirements, adding the mixed materials into a double-screw granulation system for reaction and extrusion granulation, and preparing the aromatic polyester polyurethane.

(2) Preparation of polyurethane blocked with single-ended bishydroxy polydimethylsiloxanyl ester: heating the aromatic polyurethane polyester polyurethane prepared in the step (1) to a molten state under the protection of nitrogen, adding the single-end dihydroxy polydimethyl siloxane alkyl ester into the polyurethane under the condition of stirring and mixing, and continuously stirring until the detected NCO reaches a theoretical value, thereby preparing the polyurethane blocked by the single-end dihydroxy polydimethyl siloxane alkyl ester.

(3) And (3) mixing the polyurethane terminated by the single-ended dihydroxy dimethyl siloxane alkyl ester prepared in the step (2) with an initiator for crosslinking reaction, thereby preparing the aromatic polyester type polyurethane composition terminated by the single-ended dihydroxy dimethyl siloxane alkyl ester.

Example 4 was prepared in the same manner as example 3, comparative examples 4 and 5 were prepared in the same manner except that step (3) was omitted from example 3, and comparative example 6 was prepared only in step (1) of example 3 to obtain an aromatic polyester urethane.

Table 3 shows the compositions (in parts by weight) of the components of examples 3 and 4, comparative examples 4 to 6, and Table 4 shows the results of the performance tests of the modified polyurethanes or polyurethanes obtained in examples 3 and 4, and comparative examples 4 to 6.

TABLE 3

Components	Example 3	Example 4	Comparative example 4	Comparative example 5	Comparative example 6
						MDI	25.75	25.75	25.75	25.75	25.75
PCL1000	54.82	54.82	54.82	54.82	54.82
						BDO	5.2	5.8	5.2	5.8	6.35
SP-SI3200	10	2	10	2	0
						DTBP	6	2	0	0	0

MDI: diphenylmethane diisocyanate; wanhua chemistry;

PCL 1000: polycaprolactone diol molecular weight 1000; the chemical industry of Japan xylonite corporation PCL 210N.

BDO: 1, 4-butanediol;

SP-SI 3200: a single-ended bishydroxy polydimethylsiloxanyl ester having an OH number of 9mgKOH/g and a molecular weight of 3200/1600OH gram equivalents; jidi chemical;

DTBP: di-tert-butyl peroxide industrial grade high temperature initiator; eit chemistry.

TABLE 4

As can be seen from Table 4, the aromatic polyester type polyurethane composition obtained by adding the crosslinkable SP-SI3200 group at the chain end of the TPU molecular chain and simultaneously mixing the initiator is remarkably improved in processability, abrasion resistance, gloss and tensile strength, and is remarkably reduced in water vapor transmission rate and oxygen transmission rate.

3. Aliphatic polyether urethane modification

Example 5

(1) Preparation of aliphatic polyether urethane TPU

Heating hydrogenated phenyl methane diisocyanate (H12MDI) at the temperature of 80 ℃, heating polyether polyol to 180-class 250 ℃ (preferably 180 ℃), heating 1.4 Butanediol (BDO) to 100-class 250 ℃ (preferably 100 ℃), adding the three materials into a dynamic mixer or a static mixer for rapid mixing according to the formula requirement (H12MDI stoichiometric excess) through a metering system, adding the mixed materials into a double-screw granulation system for reaction, extrusion and granulation, thereby preparing the aliphatic polyether urethane TPU.

(2) Preparation of polyurethane blocked with single-ended bishydroxy polydimethylsiloxanyl ester: heating the aromatic polyurethane polyester polyurethane prepared in the step (1) to a molten state under the protection of nitrogen, adding the single-end dihydroxy polydimethyl siloxane alkyl ester into the polyurethane under the condition of stirring and mixing, and continuously stirring until the detected NCO reaches a theoretical value, thereby preparing the polyurethane blocked by the single-end dihydroxy polydimethyl siloxane alkyl ester.

(3) And (3) mixing the polyurethane terminated by the single-ended dihydroxy polydimethyl siloxane alkyl ester prepared in the step (2) with an initiator, and then carrying out crosslinking reaction under the action of high temperature to prepare the aliphatic polyether polyurethane composition.

Example 6 was prepared in the same manner as in example 5, comparative examples 7 and 8 were prepared in the same manner, and step (3) was omitted from the preparation method of example 6, and comparative example 9 was prepared only from aliphatic polyether urethane.

Table 5 shows the compositions (in parts by weight) of the components in examples 5 and 6;

table 6 results of various property tests of aliphatic polyether type single-terminal bishydroxy polydimethylsiloxane-terminated polyurethane, aliphatic polyether polyurethane composition and polyurethane obtained in comparative examples 7 to 9

TABLE 5

H12 MDI: 4, 4-dicyclohexylmethane diisocyanate; wanhua chemistry;

PTMEG 1000: polycaprolactone diol molecular weight 1000; the chemical industry of Japan xylonite corporation PCL 210N.

BDO: 1, 4-butanediol;

SP-SI 3200: a single-ended bishydroxy polydimethylsiloxanyl ester having an OH number of 9mgKOH/g and a molecular weight of 3200/1600OH gram equivalents; jidi chemical;

DTBP: di-tert-butyl peroxide industrial grade high temperature initiator; eit chemistry.

TABLE 6

From the results in table 6, it is known that the aliphatic polyether urethane composition obtained by adding a crosslinkable SP-SI3200 group to the chain end of the TPU molecular chain and simultaneously mixing an initiator is remarkably improved in processability, abrasion resistance, tensile strength and gloss, and is remarkably reduced in water vapor transmission rate and oxygen transmission rate.

4. Modification of aliphatic polyester polyurethane

Preparation of example 7:

(1) preparation of aliphatic polyester type polyurethane TPU

Heating hydrogenated phenyl methane diisocyanate (H12MDI) at the temperature of 80 ℃, heating polyester polyol to 180-class 250 ℃ (preferably 180 ℃), heating 1.4 Butanediol (BDO) to 100-class 250 ℃ (preferably 100 ℃), adding the three materials into a dynamic mixer or a static mixer for rapid mixing according to the formula requirement (H12MDI stoichiometric excess) through a metering system, adding the mixed materials into a double-screw granulation system for reaction, extrusion and granulation, thereby preparing the aliphatic polyester type polyurethane TPU.

(2) Preparation of polyurethane blocked with single-ended bishydroxy polydimethylsiloxanyl ester: heating the aliphatic polyester polyurethane prepared in the step (1) to a molten state under the protection of nitrogen, adding the single-end dihydroxy polydimethyl siloxane alkyl ester into the polyurethane under the condition of stirring and mixing, and continuously stirring until the detected NCO reaches a theoretical value, thereby preparing the polyurethane blocked by the single-end dihydroxy polydimethyl siloxane alkyl ester.

(3) And (3) mixing the polyurethane terminated by the single-ended dihydroxy polydimethyl siloxane alkyl ester prepared in the step (2) with an initiator, and then carrying out crosslinking reaction under the action of high temperature to prepare the aliphatic polyester type polyurethane composition.

The preparation method of example 8 is the same as that of example 7, the preparation methods of comparative examples 10 and 11 are the same, and step (3) is omitted, only steps (1) and (2) are included, and comparative example 12 prepares only an aliphatic polyester type TPU, which is different from the preparation method of example 7.

Table 7 shows the compositions (in parts by weight) of the respective components in examples 7 to 8 and comparative examples 10 to 12;

table 8 shows the results of performance tests on the aliphatic polyester type single-ended bishydroxypolydimethylsiloxane-terminated polyurethane obtained in examples 7 to 8 and comparative examples 10 to 12, the aliphatic polyester type polyurethane composition, and the polyurethane.

TABLE 7

Components	Example 7	Example 8	Comparative example 10	Comparative example 11	Comparative example 12
						MDI	29.82	29.82	29.82	29.82	29.82
PCL1000	54.82	54.82	54.82	54.82	54.82
						BDO	5.2	5.8	5.2	5.8	6.35
SP-SI3200	10	2	10	2	0
						DTBP	6	2	0	0	0

H12 MDI: 4, 4-dicyclohexylmethane diisocyanate; wanhua chemistry;

PCL 1000: polycaprolactone diol molecular weight 1000; the chemical industry of Japan xylonite corporation PCL 210N.

BDO: 1, 4-butanediol;

SP-SI 3200: a single-ended bishydroxy polydimethylsiloxanyl ester having an OH number of 9mgKOH/g and a molecular weight of 3200/1600OH gram equivalents; jidi chemical;

DTBP: di-tert-butyl peroxide industrial grade high temperature initiator; eit chemistry.

TABLE 8

As can be seen from Table 8, the aliphatic polyester type polyurethane composition obtained by adding a crosslinkable SP-SI3200 group at the chain end of the TPU molecular chain and simultaneously mixing an initiator is remarkably improved in processability, abrasion resistance, tensile strength and gloss, and is remarkably reduced in water vapor transmission rate and oxygen transmission rate.

In conclusion, the single-ended double-hydroxyl polydimethylsiloxanyl ester group is introduced into the chain end of the polyurethane molecule, and after film formation, siloxanyl ester is enriched on the surface of polyurethane, so that the polyurethane film is easy to process, has excellent wear resistance and water vapor barrier property, and also improves the tensile strength of the TPU film. The polyurethane may be any of aliphatic polyurethane and aromatic polyurethane. When the polyurethane film is prepared, firstly, the single-end double-hydroxyl polydimethylsiloxanyl ester group is introduced into the chain end of a polyurethane molecule, and simultaneously, the polyurethane composition obtained by mixing the polyurethane molecule with an organic peroxide initiator is processed, the initiator can initiate the cross-linking group of the single-end double-hydroxyl polydimethylsiloxanyl ester to carry out cross-linking under the action of high temperature, and after the film is formed, the siloxanyl ester is enriched on the surface of a polyurethane film, so that the polyurethane product which is easy to process, excellent in weather resistance and excellent in water vapor barrier property is prepared.

The embodiments of the present invention have been described in detail, but the present invention is not limited to the embodiments. Even if various changes are made to the present invention, it is still within the scope of the present invention if they fall within the scope of the claims of the present invention and their equivalents.