阅读说明：本技术 聚丙交酯改性皮革用镜面树脂及其制备方法 (Mirror resin for polylactide modified leather and preparation method thereof ) 是由 舒科进 陈元昌 于 2021-01-15 设计创作，主要内容包括：本发明提供了聚丙交酯改性皮革用镜面树脂及其制备方法,该改性皮革用镜面树脂由如下聚丙交酯、聚酯多元醇、扩链剂、异氰酸酯等组分构成。本发明在合成镜面树脂时加入适量的聚丙交酯多元醇与合适的其它多元醇等材料配伍,利用聚丙交酯的透亮感和干爽性以改善常规镜面树脂的通透性能,表面干爽性能以及展色性能,有效地解决皮革用镜面树脂其透亮度不强,表面发粘,展色性不佳的弊端。将其涂布在基材上使其表面形成通透感强,亮度好,表面干爽不粘的效果,更有耐屈折性好、耐水解性优异、可生物降解等特色。(The invention provides a polylactide modified mirror resin for leather and a preparation method thereof. In the invention, a proper amount of polylactide polyol is added to be compatible with other proper polyols and other materials when the mirror resin is synthesized, and the transparency, the surface dryness and the color development of the conventional mirror resin are improved by utilizing the transparency and the dryness of the polylactide, so that the defects of low transparency, low surface stickiness and poor color development of the mirror resin for leather are effectively overcome. The coating is coated on a base material to ensure that the surface of the base material has the effects of strong permeability, good brightness, dry and non-sticky surface, and has the characteristics of good folding resistance, excellent hydrolysis resistance, biodegradability and the like.)

1. The mirror resin for polylactide modified leather is characterized in that: the mirror resin for modified leather comprises the following components in percentage by weight:

polylactide: 8 to 15 percent

Polyester polyol: 15 to 22 percent

Chain extender: 1 to 5 percent

Isocyanate: 15 to 25 percent

Solvent: 40 to 55 percent

Antioxidant: 0.01 to 0.1 percent

Organic bismuth catalyst: 0.01 to 0.1 percent

Methanol: 0.01 to 0.3 percent.

2. The specular resin for polylactide-modified leather according to claim 1, wherein: the polylactide is a 2000 molecular weight polylactide glycol, and the hydroxyl value thereof is 56 +/-3.

3. The specular resin for polylactide-modified leather according to claim 1, wherein: the polyester polyol is produced by copolymerizing acrylic acid with any one or more of ethylene glycol, butanediol, 2-methyl-1, 3-propanediol and neopentyl glycol, the molecular weight of the polyester polyol is 500-4000, and the number of hydroxyl groups is 2.

4. The specular resin for polylactide-modified leather according to claim 3, wherein: the polyester polyol is produced by copolymerizing acrylic acid, ethylene glycol and butanediol, and the molar ratio of the ethylene glycol to the butanediol is 1: 1-1: 3.

5. The specular resin for polylactide-modified leather according to claim 1, wherein: the isocyanate is one or more of diphenylmethane diisocyanate, toluene diisocyanate, isophorone diisocyanate and diphenylmethane diisocyanate.

6. The specular resin for polylactide-modified leather according to claim 1, wherein: the solvent is a dimethylformamide solvent or a mixed solvent of dimethylformamide and methyl ethyl ketone, and the mixing ratio is that the dimethylformamide: the ratio of methyl ethyl ketone is 9: 1-7: 3.

7. The specular resin for polylactide-modified leather according to claim 1, wherein: the chain extender is one or two of ethylene glycol or neopentyl glycol, and the weight ratio of ethylene glycol: the ratio of neopentyl glycol is 2: 1-4: 1.

8. The method for preparing a mirror resin for polylactide-modified leather according to claim 1, wherein: the method comprises the following steps:

the first step is as follows: adding polylactide, polyester polyol, a chain extender, an antioxidant and 60-80% of a solvent into a reaction kettle, stirring for 23-38 min, and heating to 50-70 ℃;

the second step is that: adding 45-70% of isocyanate, heating, keeping the temperature at 70-85 ℃, and reacting for 25-35 min;

the third step: firstly, adding 5-15% of solvent, then adding 10-20% of isocyanate, and reacting for 25-35 min at the temperature of 70-85 ℃;

the fourth step: firstly, adding 5-15% of solvent, then adding 8-12% of isocyanate, and reacting for 25-35 min at the temperature of 70-85 ℃;

the fifth step: adding an organic bismuth catalyst, and reacting for 25-35 min at the temperature of 70-85 ℃;

and a sixth step: adding 5-15% of isocyanate, and reacting for 25-35 min at the temperature of 70-85 ℃;

the seventh step: adding 3-10% of isocyanate, and reacting for 25-35 min at the temperature of 70-85 ℃;

eighth step: gradually correcting the isocyanate according to the reaction viscosity until the required viscosity reaches 60000-100000 CPS/25 ℃, adding methanol and 5-15% of solvent to stop the reaction, and preserving the temperature at 70-85 ℃ until 25-35 min, and then discharging and packaging.

9. The method for preparing a mirror resin for polylactide-modified leather according to claim 8, wherein: the method comprises the following steps:

the first step is as follows: adding polylactide polyol, polyester polyol, ethylene glycol, neopentyl glycol, an antioxidant and 64-76% of dimethylformamide into a reaction kettle, stirring for 28-33 min, and heating to 55-65 ℃;

the second step is that: adding 48-67% of diphenylmethane diisocyanate, keeping the temperature at 72-80 ℃, and reacting for 28-33 min;

the third step: adding 8-12% of dimethylformamide, adding 13-17% of diphenylmethane diisocyanate, and reacting for 28-33 min at the temperature of 72-80 ℃;

the fourth step: adding 8-12% of dimethylformamide, adding 8-12% of diphenylmethane diisocyanate, and reacting for 28-33 min at the temperature of 72-80 ℃;

the fifth step: adding an organic bismuth catalyst, and reacting for 28-33 min at the temperature of 72-80 ℃;

and a sixth step: adding 8-12% of diphenylmethane diisocyanate, and reacting for 28-33 min at the temperature of 72-80 ℃;

the seventh step: adding 3-7% of diphenylmethane diisocyanate, and reacting for 28-33 min at the temperature of 72-80 ℃;

eighth step: gradually correcting the diphenylmethane diisocyanate according to the reaction viscosity to the required viscosity of 60000-100000 CPS/25 ℃, adding methanol and 8-12% of dimethylformamide to stop the reaction, and preserving the temperature of 72-80 ℃ until 28-33 min, namely discharging and packaging.

Technical Field

Embodiments disclosed herein relate generally to the field of mirror resins, and more particularly, to a mirror resin for polylactide-modified leather and a method for preparing the same.

Background

Most of the prior mirror resin for leather is synthesized by common polyester, and has the defects of insufficient color development and insufficient transparency; and the surface dryness is not enough, so that the adhesion is easily caused, and particularly, the surface of the low-modulus mirror resin for leather is more prominent. The silicone is used for improving the surface stickiness phenomenon, and the abnormality of spitting caused by precipitation of silicone oil is easy to occur. Therefore, the invention aims to research and improve the defects of low brightness, sticky surface and poor color development of the mirror resin for leather.

Disclosure of Invention

In view of the problems of the prior art, the present invention provides a polylactide-modified mirror resin for leather and a method for preparing the same, which can effectively solve the problems of the prior art.

The technical scheme of the invention is as follows:

the mirror resin for the modified leather comprises the following components in percentage by weight:

polylactide: 8 to 15 percent

Polyester polyol: 15 to 22 percent

Chain extender: 1 to 5 percent

Isocyanate: 15 to 25 percent

Solvent: 40 to 55 percent

Antioxidant: 0.01 to 0.1 percent

Organic bismuth catalyst: 0.01 to 0.1 percent

Methanol: 0.01 to 0.3 percent.

Preferably, the polylactide is a 2000 molecular weight polylactide diol, and has a hydroxyl number of 56 ± 3.

Preferably, the polyester polyol is produced by copolymerizing acrylic acid and any one or more of ethylene glycol, butanediol, 2-methyl-1, 3-propanediol and neopentyl glycol, the molecular weight of the polyester polyol is 500-4000, and the number of hydroxyl groups is 2.

Preferably, the polyester polyol is produced by copolymerizing acrylic acid with ethylene glycol and butanediol, and the molar ratio of the ethylene glycol to the butanediol is 1: 1-1: 3.

Preferably, the isocyanate is one or more of diphenylmethane diisocyanate, toluene diisocyanate, isophorone diisocyanate, and diphenylmethane diisocyanate.

Preferably, the solvent is a dimethylformamide solvent or a mixed solvent of dimethylformamide and methyl ethyl ketone, and the mixing ratio is that the dimethylformamide: the ratio of methyl ethyl ketone is 9: 1-7: 3.

Preferably, the chain extender is one or both of ethylene glycol or neopentyl glycol, and the ratio of ethylene glycol: the ratio of neopentyl glycol is 2: 1-4: 1.

Further, the present invention also provides: the preparation method of the mirror resin for the polylactide modified leather comprises the following steps:

the first step is as follows: adding polylactide, polyester polyol, a chain extender, an antioxidant and 60-80% of a solvent into a reaction kettle, stirring for 23-38 min, and heating to 50-70 ℃;

the second step is that: adding 45-70% of isocyanate, heating, keeping the temperature at 70-85 ℃, and reacting for 25-35 min;

the third step: firstly, adding 5-15% of solvent, then adding 10-20% of isocyanate, and reacting for 25-35 min at the temperature of 70-85 ℃;

the fourth step: firstly, adding 5-15% of solvent, then adding 8-12% of isocyanate, and reacting for 25-35 min at the temperature of 70-85 ℃;

the fifth step: adding an organic bismuth catalyst, and reacting for 25-35 min at the temperature of 70-85 ℃;

and a sixth step: adding 5-15% of isocyanate, and reacting for 25-35 min at the temperature of 70-85 ℃;

the seventh step: adding 3-10% of isocyanate, and reacting for 25-35 min at the temperature of 70-85 ℃;

eighth step: gradually correcting the isocyanate according to the reaction viscosity until the required viscosity reaches 60000-100000 CPS/25 ℃, adding methanol and 5-15% of solvent to stop the reaction, and preserving the temperature at 70-85 ℃ until 25-35 min, and then discharging and packaging.

Preferably, the preparation method of the mirror resin for polylactide-modified leather comprises the following steps:

the first step is as follows: adding polylactide polyol, polyester polyol, ethylene glycol, neopentyl glycol, an antioxidant and 64-76% of dimethylformamide into a reaction kettle, stirring for 28-33 min, and heating to 55-65 ℃;

the second step is that: adding 48-67% of diphenylmethane diisocyanate, keeping the temperature at 72-80 ℃, and reacting for 28-33 min;

the third step: adding 8-12% of dimethylformamide, adding 13-17% of diphenylmethane diisocyanate, and reacting for 28-33 min at the temperature of 72-80 ℃;

the fourth step: adding 8-12% of dimethylformamide, adding 8-12% of diphenylmethane diisocyanate, and reacting for 28-33 min at the temperature of 72-80 ℃;

the fifth step: adding an organic bismuth catalyst, and reacting for 28-33 min at the temperature of 72-80 ℃;

and a sixth step: adding 8-12% of diphenylmethane diisocyanate, and reacting for 28-33 min at the temperature of 72-80 ℃;

the seventh step: adding 3-7% of diphenylmethane diisocyanate, and reacting for 28-33 min at the temperature of 72-80 ℃;

eighth step: gradually correcting the diphenylmethane diisocyanate according to the reaction viscosity to the required viscosity of 60000-100000 CPS/25 ℃, adding methanol and 8-12% of dimethylformamide to stop the reaction, and preserving the temperature of 72-80 ℃ until 28-33 min, namely discharging and packaging.

The invention has the advantages that:

(1) in the invention, a proper amount of polylactide polyol is added to be compatible with other proper polyols and other materials when the mirror resin is synthesized, and the transparency, the surface dryness and the color development of the conventional mirror resin are improved by utilizing the transparency and the dryness of the polylactide, so that the defects of low transparency, low surface stickiness and poor color development of the mirror resin for leather are effectively overcome. And can solve the problem that the surface stickiness is improved by adopting the traditional organosilicon system, and the abnormal problem that the silicone oil is easy to precipitate and spit fog is solved. The coating is coated on a base material to ensure that the surface of the base material has the effects of strong permeability, good brightness, dry and non-sticky surface, and has the characteristics of good folding resistance, excellent hydrolysis resistance, biodegradability and the like.

(2) The polylactide polyol is prepared by ring-opening polymerization by using lactide monomer and dihydroxy or trihydroxy as initiators, so that the molecular structure of the polylactide polyol contains a carboxyl group and a CH3 group in a side chain in addition to a conventional OH group. Therefore, the oil-resistant polyurethane elastomer has low crystallinity, good flexibility, good optical property, bright color, good chemical stability, strong cohesive strength and adhesive force and excellent oil resistance.

It should be understood that the statements herein reciting aspects are not intended to limit the critical or essential features of any embodiment of the invention, nor are they intended to limit the scope of the invention. Other features of the present invention will become apparent from the following description.

Detailed Description

Example 1

The mirror resin for the modified leather comprises the following components in percentage by weight:

2000 molecular weight polylactide glycol: 8 percent of

Polyester polyol: 15 percent of

Chain extender ethylene glycol: 1 percent of

Chain extender neopentyl glycol: 0.5 percent

Isocyanate diphenylmethane diisocyanate: 20.45 percent

Solvent dimethylformamide: 55 percent of

Antioxidant: 0.01 percent

Organic bismuth catalyst: 0.01 percent

Methanol: 0.03 percent

Wherein the hydroxyl value of the 2000 molecular weight polylactideglycol is 56 plus or minus 3; the polyester polyol is produced by copolymerizing acrylic acid, ethylene glycol and butanediol, wherein the molar ratio of the ethylene glycol to the butanediol is 1:1, the molecular weight is 500-4000, and the number of hydroxyl groups is 2.

The preparation method of the mirror resin for the polylactide modified leather comprises the following steps:

the first step is as follows: adding polylactide polyol, polyester polyol, ethylene glycol, neopentyl glycol, an antioxidant and 64% of dimethylformamide into a reaction kettle, stirring for 28min and heating to 55 ℃;

the second step is that: adding 48% of diphenylmethane diisocyanate, keeping the temperature at 72 ℃ and reacting for 33 min;

the third step: adding 12% of dimethylformamide, adding 17% of diphenylmethane diisocyanate, and reacting for 33min at the temperature of 72 ℃;

the fourth step: adding 12% of dimethylformamide, then adding 12% of diphenylmethane diisocyanate, and keeping the temperature at 72 ℃ for reacting for 33 min;

the fifth step: adding an organic bismuth catalyst, and keeping the temperature at 72 ℃ for reaction for 33 min;

and a sixth step: adding 12% of diphenylmethane diisocyanate and reacting for 33min at the temperature of 72 ℃;

the seventh step: adding 7% of diphenylmethane diisocyanate, and reacting for 28-33 min at the temperature of 72 ℃;

eighth step: gradually correcting the diphenylmethane diisocyanate according to the reaction viscosity to the required viscosity of 60000-100000 CPS/25 ℃, adding methanol and 12% dimethylformamide to stop the reaction, and keeping the temperature for 72 ℃ until 33min, thus discharging and packaging.

Example 2

The mirror resin for the modified leather comprises the following components in percentage by weight:

2000 molecular weight polylactide glycol: 15 percent of

Polyester polyol: 22 percent

Chain extender ethylene glycol: 3.5 percent

Chain extender neopentyl glycol: 1.5 percent

Isocyanate diphenylmethane diisocyanate: 17.5 percent

Solvent dimethylformamide: 40 percent of

Antioxidant: 0.1 percent of

Organic bismuth catalyst: 0.1 percent of

Methanol: 0.3 percent of

Wherein the hydroxyl value of the 2000 molecular weight polylactideglycol is 56 plus or minus 3; the polyester polyol is produced by copolymerizing acrylic acid, ethylene glycol and butanediol, wherein the molar ratio of the ethylene glycol to the butanediol is 1:1, the molecular weight is 500-4000, and the number of hydroxyl groups is 2.

The preparation method of the mirror resin for the polylactide modified leather comprises the following steps:

the first step is as follows: adding polylactide polyol, polyester polyol, ethylene glycol, neopentyl glycol, an antioxidant and 76% of dimethylformamide into a reaction kettle, stirring for 33min and heating to 65 ℃;

the second step is that: adding 67% of diphenylmethane diisocyanate, keeping the temperature at 80 ℃, and reacting for 28 min;

the third step: adding 8% of dimethylformamide, adding 13% of diphenylmethane diisocyanate, and reacting for 33min at the temperature of 80 ℃;

the fourth step: firstly adding 8% of dimethylformamide, then adding 8% of diphenylmethane diisocyanate, and keeping the temperature at 80 ℃ for reacting for 33 min;

the fifth step: adding an organic bismuth catalyst, and reacting for 33min at the temperature of 80 ℃;

and a sixth step: adding 8% of diphenylmethane diisocyanate and reacting for 33min at the temperature of 80 ℃;

the seventh step: adding 3% of diphenylmethane diisocyanate and reacting for 33min at the temperature of 80 ℃;

eighth step: gradually correcting the diphenylmethane diisocyanate according to the reaction viscosity to the required viscosity of 60000-100000 CPS/25 ℃, adding methanol and 8% of dimethylformamide to stop the reaction, and preserving the temperature for 80 ℃ until 28min, and then discharging and packaging.

Example 3

The mirror resin for the modified leather comprises the following components in percentage by weight:

2000 molecular weight polylactide glycol: 12 percent of

Polyester polyol: 18 percent of

Chain extender ethylene glycol: 2 percent of

Chain extender neopentyl glycol: 0.8 percent

Isocyanate diphenylmethane diisocyanate: 20.15 percent

Solvent dimethylformamide: 47 percent of

Antioxidant: 0.01 percent

Organic bismuth catalyst: 0.01 percent

Methanol: 0.03 percent

Wherein the hydroxyl value of the 2000 molecular weight polylactideglycol is 56 plus or minus 3; the polyester polyol is produced by copolymerizing acrylic acid, ethylene glycol and butanediol, wherein the molar ratio of the ethylene glycol to the butanediol is 1:1, the molecular weight is 500-4000, and the number of hydroxyl groups is 2.

The preparation method of the mirror resin for the polylactide modified leather comprises the following steps:

the first step is as follows: adding polylactide polyol, polyester polyol, ethylene glycol, neopentyl glycol, an antioxidant and 70% of dimethylformamide into a reaction kettle, stirring for 30min and heating to 60 ℃;

the second step is that: adding 60% of diphenylmethane diisocyanate, keeping the temperature at 75 ℃ and reacting for 30 min;

the third step: adding 10% of dimethylformamide, adding 14% of diphenylmethane diisocyanate, and reacting for 30min at the temperature of 75 ℃;

the fourth step: adding 10% of dimethylformamide, then adding 10% of diphenylmethane diisocyanate, and keeping the temperature at 75 ℃ for reaction for 30 min;

the fifth step: adding an organic bismuth catalyst, and reacting for 30min at the temperature of 75 ℃;

and a sixth step: adding 10% of diphenylmethane diisocyanate and reacting for 30min at the temperature of 75 ℃;

the seventh step: adding 5% of diphenylmethane diisocyanate and reacting for 30min at the temperature of 75 ℃;

eighth step: gradually correcting the diphenylmethane diisocyanate according to the reaction viscosity to the required viscosity of 60000-100000 CPS/25 ℃, adding methanol and 10% of dimethylformamide to stop the reaction, and preserving the temperature to 75 ℃ until 30min, then discharging and packaging.

Example 4

The mirror resin for the modified leather comprises the following components in percentage by weight:

2000 molecular weight polylactide glycol: 10 percent of

Polyester polyol: 20 percent of

Chain extender ethylene glycol: 2.8 percent of

Chain extender neopentyl glycol: 1.2 percent of

Isocyanate diphenylmethane diisocyanate: 22.9 percent

Solvent dimethylformamide: 43 percent

Antioxidant: 0.02 percent

Organic bismuth catalyst: 0.03 percent

Methanol: 0.05 percent

Wherein the hydroxyl value of the 2000 molecular weight polylactideglycol is 56 plus or minus 3; the polyester polyol is produced by copolymerizing acrylic acid, ethylene glycol and butanediol, wherein the molar ratio of the ethylene glycol to the butanediol is 1:1, the molecular weight is 500-4000, and the number of hydroxyl groups is 2.

The preparation method of the mirror resin for the polylactide modified leather comprises the following steps:

the first step is as follows: adding polylactide polyol, polyester polyol, ethylene glycol, neopentyl glycol, an antioxidant and 73% of dimethylformamide into a reaction kettle, stirring for 29min, and heating to 58 ℃;

the second step is that: adding 56% of diphenylmethane diisocyanate, keeping the temperature at 74 ℃, and reacting for 29 min;

the third step: adding 9% of dimethylformamide, adding 13-17% of diphenylmethane diisocyanate, keeping the temperature at 74 ℃, and reacting for 29 min;

the fourth step: adding 9% of dimethylformamide, adding 8-12% of diphenylmethane diisocyanate, keeping the temperature at 74 ℃, and reacting for 29 min;

the fifth step: adding an organic bismuth catalyst, keeping the temperature at 74 ℃, and reacting for 29 min;

and a sixth step: adding 8-12% of diphenylmethane diisocyanate, keeping the temperature at 74 ℃, and reacting for 29 min;

the seventh step: adding 3-7% of diphenylmethane diisocyanate, keeping the temperature at 74 ℃, and reacting for 29 min;

eighth step: gradually correcting the diphenylmethane diisocyanate according to the reaction viscosity to the required viscosity of 60000-100000 CPS/25 ℃, adding methanol and 9% of dimethylformamide to stop the reaction, keeping the temperature at 74 ℃ until 29min, and then discharging and packaging.

Experimental and test data

The prepared mirror resin of the embodiments 1 to 4 is prepared into corresponding mirror products by the following two methods and is subjected to performance detection:

the first method comprises the following steps: each 100 parts of the polylactide-modified mirror resin for leather (hereinafter referred to as "mirror resin") prepared in examples 1 to 4 and 100 parts of a common polyester were mixed with 30 parts of dimethylformamide and 50 parts of methyl ethyl ketone. Stirring to obtain mixed solution with viscosity of 2000 CPS-5000 CPS, coating the mixed solution with thickness of 0.2mm on mirror surface release paper, drying, and sequentially increasing the temperature of an oven from 80 ℃ to 130 ℃ to form a uniform transparent film without steam holes. Then coating proper primer resin on the surfaces of mirror resin and common polyester, attaching substrates such as PU leather, Erlang leather, super-strong fiber cloth, cloth and the like, and drying (the temperature of an oven is increased from 100-140 ℃ in sequence). And finally, stripping the attached base material from the mirror surface release paper to form a product.

The surface blackness of the prepared product is observed, the surface blackness of the product coated with the mirror resin prepared in the examples 1 to 4 is excellent, and the surface blackness of the product coated with the common polyester is general. The prepared products were observed for adhesion after lamination at 60 ℃ 3KG 48 hours, respectively, and the mirror resin coated products prepared in examples 1 to 4 were not adhered except for the adhesion of Erlangpi coated in example 1 after lamination, while the products coated with ordinary polyester were all adhered. The prepared products are respectively soaked in a hydrolysis-resistant 10% sodium hydroxide aqueous solution for 24 hours at normal temperature to observe the cracking condition, the mirror resin coated products prepared in examples 1-4 are not cracked except the PU leather and cloth coated in example 4 after lamination, and the products coated by common polyester all have cracking conditions.

And the second method comprises the following steps: 100 parts of mirror resin and 100 parts of common polyester are respectively mixed with 20 parts of dimethylformamide and 80 parts of butanone. Stirring into mixed liquid with the viscosity of 50-1000 CPS, uniformly attaching the mixed liquid on the surfaces of PU leather, Erlang leather and genuine leather by adopting a spraying (roller coating or direct coating can be adopted at the same time), drying after the material consumption is about 80-300 g/square meter, and sequentially increasing the temperature of an oven from 80 ℃ to 130 ℃.

The prepared products were observed for adhesion after lamination at 60 ℃ 3KG 48 hours, and the mirror resin coated products prepared in examples 1 to 4 were laminated and were not adhered except for the adhesion of the Erlang skin coated in example 1, while the products coated with ordinary polyester were all adhered. The prepared product is soaked in a hydrolysis-resistant 10% sodium hydroxide aqueous solution for 24 hours at normal temperature to observe the cracking condition, the mirror resin coated products prepared in examples 1-4 have no cracking, and the products coated by common polyester completely exist. The prepared product resists the bending condition under the normal temperature condition, the mirror surface resin coating products prepared in the examples 1-4 are more than 2 ten thousand times, the best product of the example 3 is, and the product coated by the common polyester is only about 3000 times.

In summary, the following steps: the mirror resin prepared by the invention has obviously enhanced transparency after use, no stickiness on the surface, good folding resistance and excellent hydrolysis resistance.

In order to make the objects, technical solutions and advantages of the embodiments of the present disclosure more clear, the technical solutions in the embodiments of the present disclosure are clearly and completely described, and it is obvious that the described embodiments are a part of the embodiments of the present disclosure, but not all of the embodiments. All other embodiments, which can be obtained by a person skilled in the art without any inventive step based on the embodiments of the present invention, are within the scope of the present invention.

The above description is only a preferred embodiment of the present application and is not intended to limit the present application, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, improvement and the like made within the spirit and principle of the present application shall be included in the protection scope of the present application.