CN113024861A

CN113024861A - High-toughness and high-tensile-strength TPU (thermoplastic polyurethane) film and preparation method thereof

Info

Publication number: CN113024861A
Application number: CN202110237106.3A
Authority: CN
Inventors: 曹彦斌
Original assignee: Delstar Technologies Suzhou Co Ltd
Current assignee: Delstar Technologies Suzhou Co Ltd
Priority date: 2021-03-03
Filing date: 2021-03-03
Publication date: 2021-06-25
Anticipated expiration: 2041-03-03
Also published as: CN113024861B

Abstract

The invention discloses a high-toughness and high-tensile-strength TPU film and a preparation method thereof, wherein the TPU film comprises 85-95 parts by weight of TPU master batch, 0.5-10 parts by weight of toughening agent and 1.5-8 parts by weight of auxiliary agent. The preparation method comprises the following steps: (1) premixing and drying each raw material; (2) pushing the dried raw materials into a spiral sleeve by a motor of a single-screw extruder for melting; (3) molding the molten mixture through a die to obtain an extrusion casting film; (4) cooling the cast film through a ceramic roller and a rubber roller and adjusting the thickness of the cast film; (5) and (3) cutting edges of the cast film and winding to obtain the TPU film. The TPU film prepared by the invention has uniform thickness, excellent toughness, tensile strength and fracture ductility, so that the TPU film has good repairability and good yellowing resistance, and is very suitable for the field of automobile protective films.

Description

High-toughness and high-tensile-strength TPU (thermoplastic polyurethane) film and preparation method thereof

Technical Field

The invention belongs to the field of film manufacturing, and particularly relates to a high-toughness and high-tensile-strength TPU film and a preparation method thereof.

Background

In the process of actual use of an automobile, severe weather, such as sand dust, acid rain, hail and the like, can occasionally occur in the environment, and the protective paint on the surface of the automobile is corroded, impacted and the like, so that the automobile paint is damaged and cracked, the protective measures are usually to wax and polish the surface of the automobile paint, the automobile needs to be maintained regularly, the economic burden is increased, and the time cost of an automobile owner can be increased. Under the background, more and more vehicle owners select to use the car paint protective film, and the conventional car paint protective film uses PVC, but the PVC film has the defects of easy aging, poor repairability and the like.

Thermoplastic polyurethane has attracted attention because of its excellent toughness, high strength, no toxicity, no smell, excellent hot workability and other advantages, and is widely used in automobile electronics, medical equipment, daily necessities and other fields. The TPU film is prepared by special processes such as calendering, tape casting, film blowing, coating and the like on the basis of TPU granules, and is increasingly popular with people due to excellent performance and environmental protection concept. However, during the production and use of current TPU films, tensile strength is limited and elongation at break is low, thus further limiting the repairability of the TPU film.

Disclosure of Invention

The invention aims to provide a high-toughness high-tensile-strength TPU film and a preparation method thereof.

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

the invention provides a preparation method of a high-toughness and high-tensile strength TPU film, which comprises the following steps:

(1) premixing and drying each raw material, wherein the raw materials comprise TPU master batches and a toughening agent;

(2) pushing the dried raw materials into a spiral sleeve by a motor of a single-screw extruder for melting;

(3) molding the molten mixture through a die to obtain an extrusion casting film;

(4) cooling the cast film through a ceramic roller and a rubber roller and adjusting the thickness of the cast film;

(5) and (4) cutting edges of the film obtained in the step (4) and winding to obtain the TPU film.

As a preferable technical scheme, the drying temperature in the step (1) is 120-135 DEG F, the drying time is 2-4 h, and the mass ratio of the water after drying treatment is less than or equal to 0.12%.

As a preferred technical scheme, in the step (2), the temperature of the feeding section of the single screw extruder is 245-340 DEG F, the temperature of the cylinder 1 is 245-260 DEG F, the temperature of the cylinder 2 is 295-310 DEG F, the temperature of the cylinder 3 is 315-330 DEG F, the temperature of the cylinder 4 is 325-340 DEG F, the temperature of the cylinder 5 is 335-350 DEG F, the temperature of the screen is 335-350 DEG F, and the rotation speed of the screw is 22-25 rpm.

Preferably, the die in step (3) is molded at a temperature of 335 to 350 ° f, the ceramic roller and the rubber roller in step (4) are molded at a temperature of 55 to 60 ° f, the torque of the rubber roller is 18 to 22% of the motor load, and the winding tension of the coil in step (5) is 24 to 26 psi.

As a preferable technical scheme, the raw materials in the step (1) comprise, by weight, 85-95 parts of TPU master batch, 0.5-10 parts of toughening agent and 1.5-8 parts of auxiliary agent.

As a preferred technical scheme, the toughening agent is an ethylene-methyl acrylate copolymer and a methyl methacrylate-butadiene-styrene terpolymer, and the mass ratio of the ethylene-methyl acrylate copolymer to the methyl methacrylate-butadiene-styrene terpolymer is 1: (1-1.2).

As a preferable technical scheme, the auxiliary agent comprises an antioxidant and an ultraviolet absorbent, and the mass ratio of the antioxidant to the ultraviolet absorbent is 1: 2.

as a preferable technical scheme, the antioxidant is a compound of a phosphite antioxidant and a hindered phenol antioxidant, and the mass ratio of the phosphite antioxidant to the hindered phenol antioxidant is (1-1.5): 1, the ultraviolet absorbent is 2-hydroxy-4-n-octyloxy diphenyl and 2- (2-hydroxy-5-benzyl) benzotriazole, and the mass ratio of the two is (1.0-1.2): 1.

as a preferable technical scheme, the preparation raw materials of the TPU master batch comprise the following components in parts by weight: 30-45 parts of aliphatic diisocyanate, 5-10 parts of a chain extender, 30-50 parts of polyether polyol, 0.2-0.5 part of a catalyst and 8-10 parts of polystyrene.

In another aspect of the invention, a high-toughness and high-tensile strength TPU film obtained by the preparation method is provided.

Has the advantages that:

(1) the TPU film prepared from the TPU master batch, the toughening agent and the auxiliary agent in a specific ratio has excellent toughness and tensile strength and strong repairability;

(2) the temperature of the cylinder 5 is kept close to or the same as that of the filter screen and the mouth mold die, so that the extruded casting film can be uniformly plasticized, and no impurities or un-plasticized particles exist;

(3) the ceramic roller and the rubber roller are adopted for carrying out the counter-pressing process, so that the defect that the roller is easy to stick in the traditional mirror roller is overcome, and the finally obtained TPU thin film is uniform in thickness and ranges from 4 to 6 mil;

(4) the TPU master batch is prepared into a prepolymer by polyether polyol and aliphatic diisocyanate in a specific ratio, so that the prepared TPU film has excellent toughness and tensile strength and a certain flame retardant effect;

(5) the TPU film disclosed by the invention is simple in preparation process, easy to implement, higher in efficiency, suitable for industrial large-scale production of the automobile protective film and wide in application prospect.

Detailed Description

The invention will be further understood by reference to the following detailed description of preferred embodiments of the invention and the examples included therein. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. To the extent that a definition of a particular term disclosed in the prior art is inconsistent with any definition provided in the present disclosure, the definition of the term provided in the present disclosure controls.

As used herein, a feature that does not define a singular or plural form is also intended to include a plural form of the feature unless the context clearly indicates otherwise. It will be further understood that the term "prepared from …," as used herein, is synonymous with "comprising," including, "comprising," "having," "including," and/or "containing," when used in this specification means that the recited composition, step, method, article, or device is present, but does not preclude the presence or addition of one or more other compositions, steps, methods, articles, or devices. Furthermore, the use of "preferred," "preferably," "more preferred," etc., when describing embodiments of the present invention, is meant to refer to embodiments of the invention that may provide certain benefits, under certain circumstances. However, other embodiments may be preferred, under the same or other circumstances. In addition, the recitation of one or more preferred embodiments does not imply that other embodiments are not useful, nor is it intended to exclude other embodiments from the scope of the invention.

In some preferred embodiments, the drying temperature in the step (1) is 120-135 DEG F, the drying time is 2-4 h, and the moisture mass ratio after drying treatment is less than or equal to 0.12%.

In some preferred embodiments, the temperature of the feeding section of the single screw extruder in step (2) is 245-340 ℉, the temperature of the cylinder 1 is 245-260 ℉, the temperature of the cylinder 2 is 295-310 ℉, the temperature of the cylinder 3 is 315-330 ℉, the temperature of the cylinder 4 is 325-340 ℉, the temperature of the cylinder 5 is 335-350 ℉, the temperature of the screen is 335-350 ℉ and the rotation speed of the screw is 22-25 rpm.

In some preferred embodiments, the die temperature used in the step (3) is 335-350F.

Adopt barrel 1-5 to melt the raw materials, can guarantee that the melting is even, can prevent through the filter screen that impurity and not plasticized material from passing through, make the goods more closely knit to guarantee that barrel 5 is close or the same with filter screen temperature, mould temperature, can make the curtain coating film plastify that extrudes and obtain abundant and even.

In some preferred embodiments, the ceramic and rubber rolls of step (4) have a temperature of 55 to 60 ° f, the rubber rolls have a torque of 18 to 22% of the motor load, and the wound roll of step (5) has a winding tension of 24 to 26 psi.

The ceramic roller and the rubber roller are adopted for carrying out the counter-pressing process, the defect that the roller is easy to adhere in the traditional mirror roller is overcome, the thickness of the finally obtained TPU film is uniform, the thickness range is 4-6mil, crystal points are not easy to generate, the haze value is small, and the transparency is high.

In some preferred embodiments, the raw material of step (1) comprises, by weight, 85-95 parts of TPU master batch, 0.5-10 parts of toughening agent, and 1.5-8 parts of auxiliary agent.

In some preferred embodiments, the toughening agent is an ethylene-methyl acrylate copolymer (EMA) and a methyl methacrylate-butadiene-styrene terpolymer (MBS), in a mass ratio of 1: (1-1.2).

The ethylene-methyl acrylate copolymer (EMA) is of the type of DuPont EMA 1126AC, and the methyl methacrylate-butadiene-styrene terpolymer (MBS) is purchased from Jiaqing plastics raw materials Co., Ltd, Dongguan, and is of the type of BTA-751.

In some preferred embodiments, the auxiliary agent comprises an antioxidant and an ultraviolet absorber, and the mass ratio of the antioxidant to the ultraviolet absorber is 1: 2.

in some preferred embodiments, the antioxidant is a complex formulation of a phosphite antioxidant and a hindered phenol antioxidant, and the mass ratio of the phosphite antioxidant to the hindered phenol antioxidant is (1-1.5): 1, the ultraviolet absorbent is 2-hydroxy-4-n-octyloxy diphenyl and 2- (2-hydroxy-5-benzyl) benzotriazole, and the mass ratio of the two is (1.0-1.2): 1.

in some preferred embodiments, the phosphite antioxidant comprises one of antioxidant 168, antioxidant TNP, preferably antioxidant 168, and the hindered phenol antioxidant comprises one of antioxidant 1076, antioxidant 1010, antioxidant 1035, preferably antioxidant 1076.

In some preferred embodiments, the preparation raw materials of the TPU masterbatch comprise the following components in parts by weight: 30-45 parts of aliphatic diisocyanate, 5-10 parts of a chain extender, 30-50 parts of polyether polyol, 0.2-0.5 part of a catalyst and 8-10 parts of polytetrafluoroethylene.

In some preferred embodiments, the TPU masterbatch is prepared by the following process:

(1) sequentially adding polyether polyol and aliphatic diisocyanate into a container, and carrying out vacuum reaction at the stirring speed of 400-600 r/min at the temperature of 70-85 ℃ for 12-18 h to obtain a prepolymer;

(2) adding a chain extender and a catalyst thereof into the prepolymer obtained in the step (1), and continuing vacuum reaction for 3-5 hours at the temperature of 70-85 ℃;

(3) adding polytetrafluoroethylene into the mixture reacted in the step (2), and stirring for 60-120 min; and then carrying out extrusion molding in a double-screw extruder to obtain the TPU master batch.

Preparing TPU master batches by a two-step method, preparing a prepolymer by specific polyether polyol and aliphatic diisocyanate in the step (1) under specific conditions, and then carrying out polymerization reaction in the step (2), so that the finally prepared TPU film has a good flame retardant effect.

In some preferred embodiments, the polyether polyol has a hydroxyl value of 270 to 400 mgKOH/g.

In some preferred embodiments, the aliphatic diisocyanate includes one of Hexamethylene Diisocyanate (HDI), isophorone diisocyanate (IPDI), cyclohexanedimethylene diisocyanate (H6XDI), 4' -dicyclohexylmethane diisocyanate (H12MDI), preferably cyclohexanedimethylene diisocyanate (H6 XDI).

In some preferred embodiments, the chain extender is an alcohol containing two-OH groups, specifically including one or more of 1, 3-propanediol, 2-methyl-1, 3-propanediol, 1, 4-butanediol, 1, 3-butanediol, or 1, 6-hexanediol, preferably 1, 4-butanediol.

In some preferred embodiments, the catalyst comprises any one or more of N, N-dimethylcyclohexylamine, dibutyltin dilaurate, N-ethylmorpholine.

In some preferred embodiments, the polytetrafluoroethylene is purchased from Shenyang Industrie technologies, Inc.

Examples

Example 1

The embodiment provides a high-toughness and high-tensile-strength TPU film on one hand, which comprises the following raw materials in parts by weight: 90.5 parts of TPU master batch, 1.5 parts of EMA 1126AC, 1.5 parts of BTA-751MBS, 1681.5 parts of antioxidant, 10761 parts of antioxidant, 2.5 parts of 2-hydroxy-4-n-octyloxy diphenyl and 2.5 parts of 2- (2-hydroxy-5-benzyl) benzotriazole.

Firstly, preparing TPU master batch, wherein the TPU master batch comprises the following components in parts by weight: 35 parts of polyether polyol with the hydroxyl value of 330mgKOH/g, 46 parts of cyclohexane dimethylene diisocyanate, 8.8 parts of 1, 4-butanediol, 0.2 part of N, N-dimethylcyclohexylamine and 10 parts of polytetrafluoroethylene.

(1) Sequentially adding polyether polyol with a hydroxyl value of 285mgKOH/g and cyclohexane dimethylene diisocyanate into a container, and carrying out vacuum reaction for 16h at 80 ℃ at a stirring speed of 500r/min to obtain a prepolymer;

(2) adding 1, 4-butanediol and N, N-dimethylcyclohexylamine into the prepolymer obtained in the step (1), and continuing vacuum reaction for 4 hours at 85 ℃;

(3) adding polytetrafluoroethylene into the mixture reacted in the step (2), and stirring for 100 min; and then carrying out extrusion molding in a double-screw extruder to obtain the TPU master batch.

The polytetrafluoroethylene is purchased from Shenyang Industrie technologies, Inc.

In another aspect, the present invention provides a method for preparing a high tenacity, high tensile strength TPU film, comprising the steps of:

(1) premixing prepared raw materials including TPU master batch, EMA 1126AC, BTA-751MBS, antioxidant 168, antioxidant 1076, 2-hydroxy-4-n-octyloxy diphenyl and 2- (2-hydroxy-5-benzyl) benzotriazole, drying at 130 ℉ for 3h, and testing moisture after drying, wherein the mass percentage of the moisture is less than or equal to 0.12%;

(2) pushing the component particles into a spiral sleeve by an extrusion motor to be melted after drying;

(5) and (3) carrying out edge cutting and winding treatment on the casting film with the adjusted thickness to obtain the TPU film.

In the step (2), the specific parameters are set as follows: barrel 1 temperature 250F, barrel 2 temperature 300F, barrel 3 temperature 320F, barrel 4 temperature 330F, barrel 5 temperature 340F, screen temperature 340F, screw speed 24 rpm;

in step (3) above, the die temperature for the die forming was 340 ° f;

in step (4) above, the temperature of the ceramic roller and the rubber roller is 57 ° f, and the torque of the rubber roller is 20% of the motor load;

in step (5) above, the coil had a crimp tension of 25 psi.

Example 2

The embodiment provides a high-toughness and high-tensile-strength TPU film on one hand, which comprises the following raw materials in parts by weight: 87 parts of TPU master batch, 1126AC 2 parts of EMA, 2 parts of BTA-751MBS, 1681.5 parts of antioxidant, 10761.5 parts of antioxidant, 3 parts of 2-hydroxy-4-n-octyloxy diphenyl and 3 parts of 2- (2-hydroxy-5-benzyl) benzotriazole.

The TPU masterbatch described in this example is the same as in example 1.

In the step (2), the specific parameters are set as follows: barrel 1 temperature was 255 ° f, barrel 2 temperature was 303 ° f, barrel 3 temperature was 325 ° f, barrel 4 temperature was 331 ° f, barrel 5 temperature was 344 ° f, screen temperature was 345 ° f, screw speed was 24 rpm;

in step (3) above, the die temperature for the die molding was 345 ° f;

in step (4) above, the temperature of the ceramic roller and the rubber roller is 58 ° f, and the torque of the rubber roller is 20% of the motor load;

in step (5) above, the coil had a crimp tension of 25 psi.

Comparative example 1

A high tenacity, high tensile strength TPU film and a method for making the same are provided similar to example 1, except that the TPU film comprises the following ingredients in parts by weight: 96 parts of TPU master batch, 0.5 part of EMA 1126AC, 0.5 part of BTA-751MBS, 1680.5 part of antioxidant, 10760.5 parts of antioxidant, 1 part of 2-hydroxy-4-n-octyloxy diphenyl and 1 part of 2- (2-hydroxy-5-benzyl) benzotriazole.

Performance testing

The TPU films prepared in examples 1-2 and comparative example 1 were tested for properties and the results are shown in Table 1.

1. Mechanical Property test

The tensile strength and the elongation at break are tested according to the GB/T1040.1-2006 standard;

2. yellowing resistance test

The determination is carried out according to GB/T1865-2009 standard.

Table 1 results of performance testing

Example numbering	Tensile strength/MPa	Elongation at break	Resistance to yellowing
				Example 1	36	800％	4.5 stage
Example 2	35	780％	4.5 stage
				Comparative example 1	30	700％	4 stage

As can be seen from table 1, the TPU protective film of the present invention has excellent tensile strength and fracture ductility while having a high yellowing resistance rating, and thus can be used as an automobile protective film and is excellent in repairability during use.

Although the present invention has been described in detail with reference to the foregoing embodiments, it will be apparent to those skilled in the art that modifications and variations can be made in the present invention without departing from the spirit and scope of the invention as defined by the appended claims.

Claims

1. A preparation method of a high-toughness and high-tensile strength TPU film is characterized by comprising the following steps:

2. A method for preparing a high toughness and high tensile strength TPU film as claimed in claim 1, wherein the drying temperature in step (1) is 120-135 ℉ and the drying time is 2-4 h, and the moisture mass ratio after drying treatment is less than or equal to 0.12%.

3. A method for preparing a high toughness, high tensile strength TPU film as claimed in claim 1, wherein in step (2) the temperature of the feed section of the single screw extruder is 245-340 ° F, the temperature of barrel 1 is 245-260 ° F, the temperature of barrel 2 is 295-310 ° F, the temperature of barrel 3 is 315-330 ° F, the temperature of barrel 4 is 325-340 ° F, the temperature of barrel 5 is 335-350 ° F, the temperature of the screen is 335-350 ° F, and the rotation speed of the screw is 22-25 rpm.

4. A method of making a high tenacity, high tensile strength TPU film as claimed in claim 1 wherein said die in step (3) is formed with a die temperature of 335 to 350 ° F, said ceramic and rubber rolls in step (4) are at a temperature of 55 to 60 ° F, said rubber rolls have a torque of 18 to 22% of the motor load, and said wound up roll in step (5) has a crimp tension of 24 to 26 psi.

5. The preparation method of the high-toughness high-tensile-strength TPU film according to claim 1, wherein the raw materials of the step (1) comprise, by weight, 85-95 parts of the TPU master batch, 0.5-10 parts of the toughening agent and 1.5-8 parts of the auxiliary agent.

6. A method for preparing high toughness, high tensile strength TPU film as claimed in claim 1 or 5 wherein said toughening agent is ethylene-methyl acrylate copolymer and methyl methacrylate-butadiene-styrene terpolymer in a mass ratio of 1: (1-1.2).

7. A method for preparing high toughness, high tensile strength TPU film as claimed in claim 5 wherein said auxiliary agent comprises antioxidant and ultraviolet absorber in the mass ratio of 1: 2.

8. the preparation method of the high-toughness high-tensile-strength TPU film according to claim 7, wherein the antioxidant is a compound of a phosphite antioxidant and a hindered phenol antioxidant, and the mass ratio of the phosphite antioxidant to the hindered phenol antioxidant is (1-1.5): 1, the ultraviolet absorbent is 2-hydroxy-4-n-octyloxy diphenyl and 2- (2-hydroxy-5-benzyl) benzotriazole, and the mass ratio of the two is (1.0-1.2): 1.

9. the preparation method of the high-toughness high-tensile-strength TPU film according to claim 1 or 5, wherein the TPU master batch is prepared from the following raw materials in parts by weight: 30-45 parts of aliphatic diisocyanate, 5-10 parts of a chain extender, 30-50 parts of polyether polyol, 0.2-0.5 part of a catalyst and 8-10 parts of polytetrafluoroethylene.

10. A high tenacity, high tensile strength TPU film made by the method of making as described in any of claims 1-9.