CN108976612B

CN108976612B - Multilayer composite yoga mat and production process thereof

Info

Publication number: CN108976612B
Application number: CN201810414996.9A
Authority: CN
Inventors: 夏紫阳; 魏琼
Original assignee: Hubei Xiangyuan New Material Technology Inc
Current assignee: Hubei Xiangyuan New Material Technology Inc
Priority date: 2018-05-03
Filing date: 2018-05-03
Publication date: 2020-11-06
Anticipated expiration: 2038-05-03
Also published as: CN108976612A

Abstract

The invention discloses a multilayer composite yoga mat and a production process thereof, wherein the multilayer composite yoga mat sequentially comprises a polyethylene foaming layer, a POE foaming layer and a PP/EPDM substrate from top to bottom; placing the POE foaming master slice into a foaming furnace for free foaming to obtain a POE foaming sheet; thermally compounding the PP/EPDM sheet which is not cooled and a POE foamed sheet on a calender roll to obtain a double-layer composite sheet; finally, performing free foaming on the polyethylene foaming master slice to obtain a PE foaming sheet, adhering the PE foaming sheet on the double-layer composite sheet by using an adhesive, and cutting edges and rolling to obtain the multilayer composite yoga mat; the invention adopts PP/EPDM as the base plate, increases the friction force of the yoga mat to the ground when in use, plays a role in skid resistance, and is compared with other rubber base plates.

Description

Multilayer composite yoga mat and production process thereof

Technical Field

The invention relates to the field of high polymer materials, in particular to a multilayer composite yoga mat and a production process thereof.

Background

Yoga, as an ancient exercise mode, can improve the ability of people in the aspects of physiology, psychology, emotion and spirit under the conditions of fast pace of life and high pressure of modern people, and is favored by more and more people. When yoga is carried out, a yoga mat is needed to be used, and the general yoga mat is made of one or more of NBR, PVC, TPE, natural rubber, flax and PVC or natural rubber.

The NBR yoga mat has the advantages of excellent oil resistance, higher wear resistance, better heat resistance and strong bonding force. The disadvantages are poor low temperature resistance, poor ozone resistance, poor insulation properties, slightly low elasticity, too thick and too soft and unstable. The PVC yoga mat is made of PVC foam, the material is harmless to human bodies, but the added main auxiliary materials such as the plasticizer and the anti-aging agent have toxicity, when PVC is produced, recovered and destroyed in an incinerator, or when PVC products are accidentally combusted, such as buried in garbage, dioxin (carcinogenic substance) is generated, and the inherent market proportion is gradually reduced. The flax yoga mat is a yoga mat made of natural flax added with PVC or natural rubber. The excellent antiskid performance of self, the softness is not good enough, and yoga comfort level compares TPE mat to have something poor.

Disclosure of Invention

The first purpose of the invention is to provide a multilayer composite yoga mat which has good elasticity, reduces the discomfort of the contact between human joints and a floor during sports, has the functions of smoothness, odor adsorption and environmental protection, and has excellent slip resistance and wear resistance.

In order to achieve the purpose, the invention provides a multilayer composite yoga mat, which is characterized in that: the multilayer composite yoga mat sequentially comprises a polyethylene foaming layer, a POE foaming layer and a PP/EPDM substrate from top to bottom, wherein,

the PP/EPDM substrate comprises, by weight, 30-60 parts of polypropylene resin PP, 40-70 parts of ethylene propylene diene monomer EPDM, 0.9-1.6 parts of dicumyl peroxide (DCP), 1-5 parts of a vulcanizing agent, 5-10 parts of an auxiliary crosslinking agent, 0.5-2 parts of a composite antioxidant and 1-2 parts of activated carbon;

the POE foaming layer comprises, by weight, 70-90 parts of POE, 10-30 parts of mixed low-density polyethylene, 5-10 parts of ethylene-vinyl acetate copolymerized EVA, 1-10 parts of POE foaming agent, 0.1-2 parts of POE layer modifier and 0.5-2 parts of composite antioxidant;

the polyethylene foaming layer comprises, by weight, 70-90 parts of polyethylene, 10-20 parts of ethylene-vinyl acetate copolymerized EVA, 1-10 parts of PE layer foaming agent, 0.1-2 parts of PE layer modifier, 0.5-2 parts of composite antioxidant, 1-2 parts of diatomite and 0.07-0.3 part of hindered amine light stabilizer.

Further, the PP/EPDM substrate comprises, by weight, 40-50 parts of polypropylene resin PP, 50-60 parts of ethylene propylene diene monomer EPDM, 0.9-1.6 parts of dicumyl peroxide (DCP), 2-3 parts of a vulcanizing agent, 6-8 parts of an auxiliary crosslinking agent, 0.5-1 part of a composite antioxidant and 1-2 parts of activated carbon;

the POE foaming layer comprises, by weight, 70-80 parts of POE, 15-25 parts of mixed low-density polyethylene, 7-9 parts of ethylene-vinyl acetate copolymerized EVA, 2-4 parts of POE foaming agent, 0.6-1 part of POE layer modifier and 1-2 parts of composite antioxidant;

the polyethylene foaming layer comprises, by weight, 75-80 parts of polyethylene, 15-20 parts of ethylene-vinyl acetate copolymerized EVA, 2-3 parts of PE layer foaming agent, 0.1-2 parts of PE layer modifier, 0.5-2 parts of composite antioxidant, 1-2 parts of diatomite and 0.1-0.3 part of hindered amine light stabilizer.

Still further, the polypropylene resin PP is selected from homo-polypropylene, block co-polypropylene and random co-polypropylene; wherein the melting temperature (DSC) of the polypropylene resin PP is 145-195 ℃, and the melt flow rate is 1.0-3.0 g/10 min;

the vulcanizing agent is selected from phenolic resin and sulfur;

the auxiliary crosslinking agent is selected from pentaerythritol triacrylate and trimethylolpropane triacrylate;

in the POE foaming layer, the mixed low-density polyethylene is selected from low-density polyethylene and linear low-density polyethylene,

the POE layer foaming agent is a compound foaming agent or Azobisisobutyronitrile (AIBN), wherein the compound foaming agent is composed of azodicarbonamide, sodium bicarbonate and citric acid;

the POE layer modifier is selected from zinc acetate and zinc carbonate;

in the polyethylene foaming layer, polyethylene is selected from low-density polyethylene, linear low-density polyethylene and high-density polyethylene; the melt flow rate of the polyethylene is 1.0-3.0 g/10 min;

the compound foaming agent consists of azodicarbonamide, sodium bicarbonate and citric acid;

the PE layer foaming agent is a compound foaming agent, wherein the compound foaming agent is composed of azodicarbonamide, sodium bicarbonate and citric acid;

the PE layer modifier is selected from zinc stearate and zinc oxide;

the hindered amine light stabilizer is selected from succinic acid and (4-hydroxy-2, 2,6, 6-tetramethyl-1-piperidinol), sebacic acid bis (2, 2,6, 6-tetramethyl-4-hydroxypiperidine) ester, and nitrilotris [ acetic acid (2, 2,6, 6-tetramethyl-4-hydroxypiperidine) ester ].

Furthermore, in the polypropylene resin PP, the weight ratio of the homo-polypropylene to the block co-polypropylene to the random co-polypropylene is 1: 2-7: 5-11;

the vulcanizing agent consists of sulfur and phenolic resin, wherein the weight ratio of the sulfur to the phenolic resin is 1: 2-4;

the auxiliary crosslinking agent consists of pentaerythritol triacrylate and trimethylolpropane triacrylate, wherein the weight ratio of the pentaerythritol triacrylate to the trimethylolpropane triacrylate is 1: 1-2.

Furthermore, in the POE foaming layer, the low-density polyethylene is formed by blending low-density polyethylene and linear low-density polyethylene, and the weight ratio of the low-density polyethylene to the linear low-density polyethylene is 1-3: 1;

in the POE layer foaming agent, the weight ratio of azodicarbonamide, sodium bicarbonate and citric acid is 12-16: 1-2: 1;

in the POE layer modifier, the weight ratio of zinc acetate to zinc carbonate is 1: 2-4;

the polyethylene in the polyethylene foaming layer is formed by blending low-density polyethylene, linear low-density polyethylene and high-density polyethylene, and the weight ratio of the low-density polyethylene to the linear low-density polyethylene to the high-density polyethylene is 12-16: 1-3: 1

In the PE layer foaming agent, the weight ratio of azodicarbonamide, sodium bicarbonate and citric acid is 12-16: 1-2: 1;

in the PE layer modifier, the weight ratio of zinc stearate to zinc oxide is 1-3: 1.

Still further, the compound antioxidant is composed of hindered phenol antioxidant and thioester antioxidant/phosphite antioxidant, wherein,

the hindered phenol antioxidants are tetra [ beta- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionic acid ] pentaerythritol ester (the trade name is antioxidant 1010), beta- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionic acid n-octadecyl ester (the trade name is antioxidant 1076) and 2, 2' -thiobis [3- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate ] (the trade name is antioxidant SKY-1035);

the thioester antioxidant is distearyl thiodipropionate (the trade name is antioxidant DSTP);

the phosphite antioxidant is selected from tris (2, 4-di-tert-butyl) phenyl phosphite (trade name is antioxidant PKY-168) and bis (2, 4-di-tert-butylphenyl) (trade name is antioxidant JC-242);

still further, in the PP/EPDM substrate, the compound antioxidant used is composed of a hindered phenol antioxidant and a thioester antioxidant, and is composed of pentaerythritol tetrakis [ β - (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate ] (antioxidant 1010), distearyl thiodipropionate (antioxidant DSTP), and 2, 2' -thiobis [3- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate ] (antioxidant SKY-1035); the weight ratio of the antioxidant 1010 to the antioxidant DSTP to the antioxidant SKY-1035 is 2-5: 1: 2-5;

in the POE foaming layer, the compound antioxidant consists of hindered phenol antioxidant and phosphite antioxidant, and consists of n-octadecyl beta- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate (antioxidant 1076), bis (2, 4-di-tert-butylphenyl) (antioxidant JC-242) and tris (2, 4-di-tert-butyl) phenyl phosphite (antioxidant PKY-168); wherein the weight ratio of the antioxidant 1076, the antioxidant JC-242 and the antioxidant PKY-168 is 7-9: 1-2: 1;

in the polyethylene foaming layer, the compound antioxidant consists of hindered phenol antioxidant and phosphite antioxidant, and consists of n-octadecyl beta- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate (antioxidant 1076) and tris (2, 4-di-tert-butyl) phenyl phosphite (antioxidant PKY-168); wherein the weight ratio of the antioxidant 1076 to the antioxidant 168 is 2-5: 1.

Still further, the multilayer composite yoga mat sequentially comprises a polyethylene foaming layer, a POE foaming layer and a PP/EPDM substrate from top to bottom, wherein,

the PP/EPDM substrate comprises 60 parts of polypropylene resin PP, 40 parts of ethylene propylene diene monomer EPDM, 1.5 parts of dicumyl peroxide (DCP), 2 parts of a vulcanizing agent, 6 parts of an auxiliary crosslinking agent, 0.8 part of a compound antioxidant and 1.2 parts of activated carbon; wherein the content of the first and second substances,

the polypropylene resin PP consists of homopolymerized polypropylene, block copolymerized polypropylene and random copolymerized polypropylene, wherein the weight ratio of the homopolymerized polypropylene to the block copolymerized polypropylene to the random copolymerized polypropylene is 1: 3: 6;

the vulcanizing agent consists of sulfur and phenolic resin, wherein the weight ratio of the sulfur to the phenolic resin is 1: 4;

the auxiliary crosslinking agent consists of pentaerythritol triacrylate and trimethylolpropane triacrylate, wherein the pentaerythritol triacrylate and the trimethylolpropane triacrylate are in a weight ratio of 1: 1-2;

the compound antioxidant consists of tetra [ beta- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionic acid ] pentaerythritol ester (antioxidant 1010), distearyl thiodipropionate (antioxidant DSTP) and 2, 2' -thiobis [3- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate ] (antioxidant SKY-1035) according to the weight ratio of 3: 1: 3;

the POE foaming layer comprises raw materials of, by weight, 80 parts of POE, 20 parts of mixed low-density polyethylene, 6 parts of EVA (ethylene-vinyl acetate copolymer), 3 parts of POE foaming agent, 1 part of POE modifying agent and 0.8 part of composite antioxidant;

the mixed low-density polyethylene is formed by blending low-density polyethylene and linear low-density polyethylene according to the weight ratio of 3: 1;

the POE layer foaming agent is formed by mixing azodicarbonamide, sodium bicarbonate and citric acid according to the weight ratio of 8: 1;

in the POE layer modifier, the weight ratio of zinc acetate to zinc carbonate is 1: 2;

the polyethylene foaming layer comprises, by weight, 80 parts of polyethylene, 15 parts of ethylene-vinyl acetate copolymerized EVA, 2 parts of PE layer foaming agent, 0.5 part of PE layer modifier, 1 part of composite antioxidant, 1.2 parts of diatomite and 0.2 part of hindered amine light stabilizer.

In the polyethylene foam layer,

the polyethylene is formed by blending low-density polyethylene, linear low-density polyethylene and high-density polyethylene, and the weight ratio of the low-density polyethylene to the linear low-density polyethylene to the high-density polyethylene is 13: 2: 1;

in the PE layer foaming agent, the weight ratio of azodicarbonamide, sodium bicarbonate and citric acid is 13: 1;

the PE layer modifier is composed of zinc stearate and zinc oxide according to the weight ratio of 2: 1.

Furthermore, the yoga mat is 4.0-8.0 mm thick, wherein the polyethylene foam layer, the POE foam layer and the PP/EPDM substrate are 2-4 mm thick, 1-2 mm thick and 1-2 mm thick respectively;

wherein the Shore hardness of the polyethylene foaming layer is 25-30A; the Shore hardness of the POE foaming layer is 30-40A, and the compression ratio is 50% -85%; the PP/EPDM substrate is 40-60A;

the resilience of the multilayer composite yoga mat is 70-85%.

The second purpose of the invention is to provide a production process of the multilayer composite yoga mat.

In order to achieve the purpose, the invention provides a production process of the multilayer composite yoga mat, which comprises the following steps:

1) preparation of PP/EPDM masterbatch

a. Weighing polypropylene resin PP, ethylene propylene diene monomer EPDM, dicumyl peroxide DCP, a vulcanizing agent, an auxiliary crosslinking agent, a composite antioxidant and active carbon according to the weight part ratio of the raw materials of the PP/EPDM substrate;

b. firstly, respectively drying polypropylene resin PP and EPDM at the temperature of 70-90 ℃ for 2-4 h, then fully and uniformly mixing dicumyl peroxide (DCP), a vulcanizing agent, an auxiliary crosslinking agent, a compound antioxidant and activated carbon in a high-speed mixer to obtain a mixture, then fully mixing the dried polypropylene resin PP and EPDM and the mixture in an internal mixer, and carrying out single-screw extrusion granulation to obtain PP/EPDM master batches;

2) preparation of POE foamed substrate

a. Weighing ethylene-octene copolymer POE, mixed low-density polyethylene, ethylene-vinyl acetate copolymer EVA, a foaming agent, a modifier and a compound antioxidant according to the weight part ratio of the raw materials of the POE foaming layer;

b. mixing 5-15 parts of mixed low-density polyethylene with a foaming agent and a modifier at a high speed at normal temperature, and then carrying out banburying extrusion granulation to obtain modified foaming master batches;

c. mixing 5-10 parts of mixed low-density polyethylene and a composite antioxidant at high speed at normal temperature, and then carrying out banburying extrusion granulation to obtain antioxidant master batches;

d. mixing the modified foaming agent master batch, the antioxidant master batch, ethylene-vinyl acetate copolymer EVA, ethylene-octene copolymer POE and the rest of mixed low-density polyethylene, and extruding into sheets by using an extruder to obtain POE foamed substrates;

e. carrying out electron irradiation crosslinking on the POE foamed substrate, wherein the electron energy of the irradiation crosslinking is 0.1-4 MeV; the irradiation dose is 10-35 Mm Delar, and the crosslinking degree is controlled to be 30-60 percent, so that the POE foaming master slice is obtained;

3) preparation of polyethylene foamed substrate

a. Weighing polyethylene, ethylene-vinyl acetate copolymerized EVA, a foaming agent, a modifier, a compound antioxidant and active carbon according to the weight part ratio of the raw materials of the polyethylene foaming layer;

b. mixing 20-40 parts of polyethylene, a foaming agent and a modifier at high speed at normal temperature, and then carrying out banburying extrusion granulation to obtain modified foaming master batches;

c. mixing 10-30 parts of polyethylene and a composite antioxidant at a high speed at normal temperature, and then carrying out banburying extrusion granulation to obtain antioxidant master batches;

d. mixing the modified foaming agent master batch, the antioxidant master batch, EVA (ethylene vinyl acetate), active carbon and the balance of PE (polyethylene), and extruding into sheets by using an extruder to obtain a polyethylene foamed substrate;

e. carrying out electron irradiation crosslinking on the PE foamed substrate, wherein the electron energy of the irradiation crosslinking is 0.1-4 MeV; the irradiation dose is 15-40 Mrad, and the crosslinking degree is controlled to be 35-65%, so that the PE foaming master slice is obtained;

4) integral subsequent processing

a. Subjecting the obtained PP/EPDM master batch to a double-screw extruder at 165-195 ℃ and at a shear rate of 450s^-1Extruding the mixture into PP/EPDM sheets through dynamic vulcanization;

b. meanwhile, placing the POE foaming master slice into a foaming furnace for free foaming, wherein the foaming temperature is 280-340 ℃, and obtaining a POE foaming sheet; thermally compounding the PP/EPDM sheet which is not cooled and a POE foamed sheet on a calender roll to obtain a double-layer composite sheet;

c. and finally, carrying out free foaming on the polyethylene foaming master slice at a foaming temperature of 260-330 ℃ to obtain a PE foaming sheet, gluing and attaching the PE foaming sheet on a double-layer composite sheet, cutting edges and rolling to obtain the multilayer composite yoga mat, wherein the multilayer composite yoga mat sequentially comprises a polyethylene foaming layer, a POE foaming layer and a PP/EPDM substrate from top to bottom.

The invention has the beneficial effects that:

the invention adopts PP/EPDM as the substrate, increases the friction force of the yoga mat to the ground when in use, plays a role in skid resistance, compared with other rubber substrates, in a PP/EPDM system, EPDM is dispersed in a PP matrix and serves as crystal nuclei, EPDM is finely and uniformly distributed in the PP matrix, the number of the crystal nuclei is increased, the PP crystallization speed is increased, and more and finer PP crystals are finally formed, thereby improving the toughness and the impact strength of the material. Meanwhile, the friction force of the yoga mat to the ground is increased, and the anti-skidding effect is achieved.

The invention adopts a dynamic vulcanization technology, accelerates the production efficiency of the traditional rubber, and the PP/EPDM substrate can be recycled, thereby being safe and environment-friendly and having excellent performance; the middle layer is made of POE foaming material, so that the elastic resilience is good, and the foaming material is bonded with the substrate more closely and is not easy to fall off by using a thermal compounding technology; the surface layer adopts PE foaming material, makes the yoga mat sense of touch good, alleviates the discomfort of human joint and floor contact during the motion.

Detailed Description

In order to better explain the invention, the following further illustrate the main content of the invention in connection with specific examples, but the content of the invention is not limited to the following examples.

A multi-layer composite yoga mat comprises a polyethylene foaming layer, a POE foaming layer and a PP/EPDM substrate from top to bottom in sequence, wherein,

the PP/EPDM substrate comprises, by weight, 30-60 parts of polypropylene resin PP, 40-70 parts of ethylene propylene diene monomer EPDM, 1.2-1.6 parts of dicumyl peroxide (DCP), 1-5 parts of a vulcanizing agent, 5-10 parts of an auxiliary crosslinking agent, 0.5-2 parts of a composite antioxidant and 1-2 parts of activated carbon;

the POE foaming layer comprises, by weight, 70-90 parts of POE, 10-30 parts of polyethylene, 5-10 parts of EVA (ethylene-vinyl acetate copolymer), 1-10 parts of foaming agent, 0.1-2 parts of modifier and 0.5-2 parts of composite antioxidant;

the polyethylene foaming layer comprises, by weight, 70-90 parts of polyethylene, 10-20 parts of ethylene-vinyl acetate copolymerized EVA, 1-10 parts of a foaming agent, 0.1-2 parts of a modifier, 0.5-2 parts of a compound antioxidant, 1-2 parts of activated carbon and 0.07-0.3 part of a hindered amine light stabilizer.

The production process of the multilayer composite yoga mat comprises the following steps:

1) preparation of PP/EPDM masterbatch

2) preparation of POE foamed substrate

a. Weighing ethylene-octene copolymer POE, polyethylene, ethylene-vinyl acetate copolymer EVA, a foaming agent, a modifier and a compound antioxidant according to the weight part ratio of the raw materials of the POE foaming layer;

b. mixing 5-15 parts of polyethylene, a foaming agent and a modifier at high speed at normal temperature, and then carrying out banburying extrusion granulation to obtain modified foaming master batches;

c. mixing 5-10 parts of polyethylene and a composite antioxidant at a high speed at normal temperature, and then carrying out banburying extrusion granulation to obtain antioxidant master batches;

d. mixing the modified foaming agent master batch, the antioxidant master batch, ethylene-vinyl acetate copolymer EVA, ethylene-octene copolymer POE and the rest polyethylene, and extruding into sheets by using an extruder to obtain POE foamed substrates;

3) preparation of polyethylene foamed substrate

4) integral subsequent processing

The following formula raw materials are purchased from the market, wherein,

pentaerythritol tetrakis [ beta- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate ] (trade name: antioxidant 1010),

n-octadecyl beta- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate (trade name: antioxidant 1076),

2, 2' -thiobis [3- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate ] (trade name antioxidant SKY-1035),

the thioester antioxidant is distearyl thiodipropionate (the trade name is antioxidant DSTP),

the phosphite antioxidant is selected from tris (2, 4-di-tert-butyl) phenyl phosphite (the trade name is antioxidant PKY-168),

bis (2, 4-di-tert-butylphenyl) (trade name: antioxidant JC-242);

the melting temperature (DSC) of the polypropylene resin PP is 145-195 ℃, and the melt flow rate is 1.0-3.0 g/10 min;

the theoretical basis of the invention is that the formula and the preparation method are combined to compare the use effects of different raw materials and components:

1. effect of different Polypropylene resin PP usage on PP/EPDM

TABLE 1 Effect of different Polypropylene resins PP on PP/EPDM toughness

As shown in table 1: the homo-polypropylene has higher strength, but has poor impact strength, poor toughness and poor long-term thermal stability, and the addition amount of the homo-polypropylene is not too high when the homo-polypropylene is blended with EPDM; the ethylene content in the block copolymerization polypropylene is 7-15%, and the toughness of the polypropylene is improved and the impact strength is improved due to the addition of ethylene molecules; the random copolymerization polypropylene contains 1-4% of ethylene, and is randomly distributed on long chains in the polypropylene, so that the crystallinity and the melting point of the polymer are reduced, the impact and the long-term heat aging resistance of the material are improved, and the performance in the material is optimal. In order to ensure that the comprehensive performance of the material is better, three kinds of polypropylene are blended according to the weight ratio of 1: 2-7: 5-11, the weight ratio of the homo-polypropylene to the block co-polypropylene to the random co-polypropylene is 1: 2-7: 5-11, a small amount of homo-polypropylene is added, the tensile strength and the hardness of the material can be improved, the processability cannot be reduced, and the addition of the block and random polypropylene mainly improves the elongation at break and the impact toughness of the material.

2. Effect of PP/EPDM blending in different weight ratios on PP/EPDM Performance

TABLE 2 Effect of PP/EPDM blending in different weight ratios on PP/EPDM Performance

PP/EPDM content (parts)

30/70

35/65

40/60

45/55

50/50

60/40

Index of toughness (% elongation at break)

250～300

500～600

300～350

280～350

150～200

Hardness of

35

40

52

58

63

77

As shown in table 2: EPDM is a rubber, toughness and elasticity itself is better, but its hardness and strength are not high enough, so when PP is blended with it, its hardness will be improved when PP content is increased, and when dynamic vulcanization, there is an optimal ratio 4/6 between PP and EPDM, and then the thermoplastic elastomer properties obtained are best. As the PP content increases, the EPDM/PP crosslink level decreases. As the EPDM content increases, the hardness, tensile strength and processing flowability of the blend decrease, but the elasticity and impact strength increase, and when the EPDM content exceeds 60%, the strength gradually decreases, so that when the compounding ratio is 4/6, the EPDM and PP form two continuous phases, and the performance is best.

3. Selection of melting temperature of Polypropylene resin PP

The melting temperature (DSC) of the polypropylene resin PP is 145-195 ℃, too high or too low melting temperature has great influence on the processing performance, and too low melting temperature causes the PP to melt too early, at the moment, the rubber is not vulcanized yet, the average particle size of the rubber is increased, so that the two phases are dispersed unevenly, and the performance of the material is influenced; when the melting temperature is too high, vulcanization reversion of the rubber may occur at high temperature, and the crosslinking density is reduced, so that the mechanical property of the material is insufficient. Therefore, the optimal melting temperature is 175-185 ℃.

4. Selection of melt flow Rate of Polypropylene resin PP

The melt flow rate of the polypropylene resin PP is 1.0-3.0 g/10min, and the melt flow rate is too high or too low, which affects the flow rates of PP and EPDM during mixing, so that the two phases are not uniformly dispersed, and the optimal flow rate is 2.0g/10 min.

5. Selection of the amount of dicumyl peroxide (DCP)

Dicumyl peroxide (DCP) in 0.9-1.6 weight portions; dicumyl peroxide (DCP) is used as an initiator, can be used as an initiator of EPDM (ethylene-propylene-diene monomer) and can also play a role in inhibiting the degradation of PP in the processing process, when the content is 1.2 parts, the EPDM can be completely crosslinked, the dispersion particle size and the dispersion degree are optimal, the impact strength reaches a maximum value, the processing flowability is good, the crosslinking effect and the degradation effect of the PP are balanced, the tensile strength of the material is not reduced, and the preferable dosage is 1.2-1.6 parts.

6. Selection of vulcanizing agent

The EPDM/PP thermoplastic elastomer material obtained by using the sulfur as a vulcanizing agent has good mechanical properties such as tensile strength, elongation at break, tearing strength and dynamic fatigue, but has poor processability; the phenolic resin is used as a vulcanizing agent, has good heat resistance, high tensile strength and good processing performance, but has larger hardness and compression permanent deformation. The method comprises the following steps of (1) adopting sulfur and phenolic resin as a composite vulcanizing agent, wherein the weight ratio of the sulfur to the phenolic resin is 1: 2-4; wherein, when the weight ratio of the sulfur to the phenolic resin is 1: 4, the processing performance is greatly improved, and the comprehensive performance of the material is better. And a small amount of sulfur helps to inhibit the degradation of PP.

7. The assistant crosslinking agent is selected

Pentaerythritol triacrylate is preferred: trimethylolpropane triacrylate is 1: 1, the two auxiliary crosslinking agents play a role in promoting the crosslinking of PP and inhibiting the degradation of PP in the processing process, and the two auxiliary crosslinking agents are liquid oily substances and play a role in internal lubrication in the processing process, so that the shearing force is reduced, the vulcanization speed of the material is reduced, and the performance of the material is influenced, and the dosage is not too much, preferably 5-10 parts, and further preferably 6 parts.

8. Selection of hindered phenol antioxidant and thioester antioxidant

In the PP/EPDM substrate, the compound antioxidant consists of hindered phenol antioxidant and thioester antioxidant, the dosage of the compound antioxidant is 0.5-2 parts, and the compound antioxidant consists of tetra [ beta- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionic acid ] pentaerythritol ester (antioxidant 1010), distearyl thiodipropionate (antioxidant DSTP) and 2, 2' -thiobis [3- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate ] (antioxidant SKY-1035); the weight ratio of the antioxidant 1010 to the antioxidant DSTP to the antioxidant SKY-1035 is 2-5: 1: 2-5; the antioxidant 1010 and the antioxidant SKY-1035 are phenolic antioxidants, wherein 1010 is mainly used on PP, SKY-1035 is mainly used on rubber materials, and the antioxidant DSTP is an auxiliary antioxidant and can generate a synergistic effect with the phenolic antioxidants, so that the antioxidant effect is better. If the antioxidant content is too small, the antioxidant effect is not remarkable, and if it is too large, precipitation occurs, so that the amount of the antioxidant to be added is preferably 0.5 to 2 parts, more preferably 0.8 part.

9. Selection of active carbon

Because the density of the activated carbon is smaller than that of the zeolite molecular sieve, the activated carbon can be more easily and uniformly mixed with a resin material in the processing process, and the addition of the activated carbon has a reinforcing effect on the material, so that the tensile strength of the activated carbon is superior to that of the zeolite molecular sieve. The particle size of the powder is 100-200 meshes, the extrusion process is unstable and uneven in dispersion due to the excessively large particle size, agglomeration is easy to occur due to the excessively small particle size, and the powder is unevenly distributed in the resin. The addition amount is preferably 1 to 2 parts, and more preferably 1.2 parts, and too small amount results in insignificant adsorption effect, and too large amount results in reduced mechanical properties of the material.

II, POE foaming layer:

1. the influence of POE and PE selected according to different weight parts on the performance of the POE foaming layer

TABLE 3 influence of POE on the properties of the POE foamed layer

POE content	100	90	80	70	60
						Compression ratio (%)	88％	85％	72％	54％	40％
Tensile Strength (kPa)	10	15	24	30	35

TABLE 4 influence of PE on POE foaming layer Properties in different weight parts

PE content (%)	5	10	20	30	40
						Compression ratio (%)	86％	84％	70％	55％	38％
Tensile Strength (kPa)	12	18	25	32	36

As shown in table 3: POE is used as an elastomer, and can provide the foaming material with larger rebound resilience and compression ratio, when the content of POE is too low, the hardness of a foaming layer is increased, the elasticity is weakened, the elongation at break of the material is reduced, and the rebound resilience is reduced; when the content is too high, the tensile strength is too low, the hardness is soft, and the properties are deteriorated.

As shown in table 4: compared with POE, the PE has relatively higher hardness and strength, the tensile strength of the material can be improved by adding a proper amount of PE, but the elasticity of the foaming layer is weakened by excessive PE, so that the rebound resilience is insufficient; while too little PE will result in a material that is not strong enough to be readily stretch thinned during later processing. The POE dosage is 70-90 parts, and the PE dosage is 10-30 parts. Further preferably, the POE is 70-80 parts, and the PE is 15-25 parts.

2. Influence of different PE selection on POE foaming layer performance

TABLE 5 influence of different PE choices on POE foaming layer Performance

As shown in table 5: preferably two polyethylenes are blended, a low density polyethylene: the weight ratio of the linear low-density polyethylene is 1-3: 1, and the addition of LLDPE greatly improves the tensile strength of the material, but reduces the processability. When the content of the linear low density polyethylene is reduced, the tensile strength of the material is insufficient; when the linear low density polyethylene content is increased, processability of the blended resin is decreased, pre-decomposition of the blowing agent is caused, and elongation at break is decreased.

2. Ethylene-vinyl acetate copolymer EVA

The VA content in the EVA is 10% -20%, the VA content is high, so that the foamed POE layer is softer and has certain viscosity, and the subsequent thermal compounding process is promoted. The mechanical property of the material is reduced little by adding a small amount of EVA, but the processing property is greatly improved.

3. Selection of POE foaming agent

The POE foaming agent is a compound foaming agent or Azodiisobutyronitrile (AIBN); the composite foaming agent mainly comprises azodicarbonamide, sodium bicarbonate and citric acid,

in the compound type foaming agent, the weight ratio of azodicarbonamide, sodium bicarbonate and citric acid is 12-16: 1-2: 1; the foaming agent is a heat absorption and release balance foaming agent, the temperature of the material cannot rise due to decomposition and heat release of the foaming agent during foaming, so that the foaming process is more stable, the sizes of bubbles are consistent, and the addition amount of the foaming agent under the same multiplying power is more than that of the foaming agent under the same multiplying power due to the fact that the foaming amount of the foaming agent is lower than that of the foaming agent under the AC. The optimum amount is portion, the rebound resilience and compression ratio of the foaming layer are larger, and the tensile strength and the elongation rate are not reduced much.

4. Selecting POE layer modifier

The POE layer modifier is composed of zinc acetate and zinc carbonate according to the weight ratio of 1: 2-4, and the zinc ion outer layer has a hollow orbit which can generate a complex reaction with lone pair electrons in the foaming agent, so that the activation energy is reduced, the decomposition temperature of the foaming agent is reduced, and the POE layer modifier is favorable for the processing temperature in the subsequent foaming process. When the total amount of the modifier is 1 part, the decomposition temperature of the foaming agent is reduced to about 170 ℃, so that the resin can be foamed at a lower temperature, and the foaming speed is higher.

5. Hindered phenol antioxidant and phosphite antioxidant

In the POE foaming layer, the compound antioxidant consists of hindered phenol antioxidant and phosphite antioxidant, and consists of n-octadecyl beta- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate (antioxidant 1076), bis (2, 4-di-tert-butylphenyl) (antioxidant JC-242) and tris (2, 4-di-tert-butyl) phenyl phosphite (antioxidant PKY-168); wherein, the antioxidant 1076: antioxidant JC-242: the weight ratio of the antioxidant PKY-168 is 7-9: 1-2: 1;

the antioxidant 1076 is the main antioxidant of polyethylene, has good compatibility with resin and high antioxidant performance; the antioxidant JC-242 and the antioxidant PKY-168 are both auxiliary antibiotics, have good synergistic effect with 1076, have good processing performance, can be used at higher processing temperature, and are preferably added in an amount of 0.9 part.

Thirdly, a polyethylene foaming layer:

1. selection of polyethylene

(1) Preferred low density polyethylenes: the weight ratio of the linear low-density polyethylene to the high-density polyethylene is 12-16: 1-3: 1, polyethylene with different densities is blended, a melting area can be widened, crystallization can be delayed when a molten material is cooled, the foaming process is easier to carry out due to the characteristic, and when the low-density polyethylene is more, the foam plastic is softer, and the touch feeling is better. The addition of a small amount of linear low density polyethylene can improve the elongation at break of the material, and the addition of a small amount of high density polyethylene can improve the tensile strength of the material, but too much increases the hardness of the material and has poor processability.

TABLE 6 Effect of different types of polyethylene on the foamed polyethylene layer

(2) The polyethylene is selected

The preferable amount of the polyethylene is 70-90 parts, and theoretical explanation is as follows: when PE and EVA are blended, the hardness of the material can be increased along with the increase of the content of PE, the rebound resilience can be weakened, but the tensile strength can be improved; when the content of EVA is increased, the processability of the material is improved, and the subsequent foaming process is promoted.

2. Ethylene-vinyl acetate copolymer (EVA) selection

The content of vinyl acetate in the ethylene-vinyl acetate copolymer is not more than 10%, the EVA is softer than LDPE at the moment and has good impact strength, when the content of the EVA in the blending material is increased, the melt viscosity of a blending system is reduced, the expansion of foam holes is facilitated under the condition of the same gas forming amount and crosslinking density, the apparent density of the PE foaming layer is reduced, the hardness is reduced at the moment, the touch feeling when the PE foaming layer is in contact with a human body is better, the flexibility and the impact resistance of the foaming layer are improved, but the mechanical property is reduced along with the increase of the content of the EVA.

TABLE 7 Effect of different EVA content on polyethylene foam layer

EVA content	5	10	15	20	25
						Density g/cm³	0.108	0.105	0.1	0.096	0.093
Rebound resilience	74％	77％	79％	81％	82％
						Compression	70％	72％	75％	79％	83％
Hardness of	62	40	34	25	20
						Elongation at break%	480	475	462	383	267

3. PE layer foaming agent selection

The PE layer foaming agent is a composite foaming agent, and in the composite foaming agent, the weight ratio of azodicarbonamide, sodium bicarbonate and citric acid is 12-16: 1-2: 1; the dosage of the composition is 1-10 parts; theoretical explanation: the azodicarbonamide foaming agent has smaller particle size and is more easily dispersed during mixing, and foam holes obtained during foaming are small foam holes, so that the resilience of foam is improved; and the azodicarbonamide has large gas forming amount, can generate a large amount of gas with small addition amount, and can reduce the decomposition temperature to 175-185 ℃ by adding active substances, thereby promoting the foaming process.

4. PE layer modifier selection

The PE layer modifier is 0.1-2 parts by weight, zinc stearate and zinc oxide are used in the PE layer modifier according to the weight ratio of 1-3: 1, lone pair electrons are contained in N and O in azodicarbonamide, an empty rail is arranged on the outer layer of zinc ions, and the two are complexed, so that the concentration of N-C electron cloud becomes thin, and finally an N-C bond is broken, and the effect of activating the azodicarbonamide is achieved. The amount of zinc oxide should not be too great since it leads to too severe decomposition of azodicarbonamide. When the content of the modifier is 0.5 part, the decomposition temperature of the foaming agent is reduced to about 175 ℃, so that the temperature in the foaming process is not too high, and the expansion of gas in the resin melt is facilitated.

5. Selection of composite antioxidant

The antioxidant 1076 is a main antioxidant of polyethylene, the light stabilizer GW-622 has good compatibility with the polyethylene, and can play a good role in light stability and oxygen resistance when being compounded with the antioxidant 168, and the weight ratio of the antioxidant 1076 to the antioxidant 168 is preferably 2-5: 1. The content of the compound antioxidant is preferably 0.5-2 parts.

6. The kieselguhr has a microporous structure and a larger specific surface area, so that the kieselguhr not only can remove peculiar smell and moisture as an adsorbent, but also can load foaming agent particles in a mixing process, so that the number of foam holes is increased in a foaming process, the size of the foam holes is reduced, the kieselguhr is favorable for the softness of materials, and the touch feeling is better. The diatomite has the length of 20-40 mu m and the diameter of 10-15 mu m, and is better dispersed in the resin, and the dosage is preferably 1-2 parts, and more preferably 1.2 parts, so that the mechanical property of the material is not greatly influenced, and the material and the elongation are reduced due to excessive dosage.

Example 1

The multi-layer composite yoga mat 1 comprises a polyethylene foaming layer, a POE foaming layer and a PP/EPDM substrate from top to bottom in sequence, wherein,

the PP/EPDM substrate comprises 60 parts of polypropylene resin PP, 40 parts of ethylene propylene diene monomer EPDM, 1.5 parts of dicumyl peroxide (DCP), 2 parts of vulcanizing agent, 6 parts of auxiliary crosslinking agent, 0.8 part of compound antioxidant and 1.2 parts of activated carbon; wherein the content of the first and second substances,

the polypropylene resin PP consists of homopolymerized polypropylene, block copolymerized polypropylene and random copolymerized polypropylene, wherein the weight ratio of the homopolymerized polypropylene to the block copolymerized polypropylene to the random copolymerized polypropylene is 1: 3: 6; the melting temperature (DSC) of the polypropylene resin PP is 145-195 ℃, and the melt flow rate is 1.0-3.0 g/10 min;

the auxiliary crosslinking agent consists of pentaerythritol triacrylate and trimethylolpropane triacrylate, wherein the weight ratio of the pentaerythritol triacrylate to the trimethylolpropane triacrylate is 1: 1;

the compound antioxidant consists of an antioxidant 1010, an antioxidant DSTP and an antioxidant SKY-1035 according to the weight ratio of 3: 1: 3.

The POE foaming layer comprises 80 parts of ethylene-octene copolymer POE, 20 parts of mixed low-density polyethylene, 6 parts of ethylene-vinyl acetate copolymer EVA, 3 parts of POE layer foaming agent, 1 part of POE layer modifier and 0.8 part of composite antioxidant in parts by weight;

the POE layer modifier consists of zinc acetate and zinc carbonate according to the weight ratio of 1: 2;

In the polyethylene foaming layer, the polyethylene is formed by blending low-density polyethylene, linear low-density polyethylene and high-density polyethylene, and the weight ratio of the low-density polyethylene to the linear low-density polyethylene to the high-density polyethylene is 13: 2: 1

The production process of the multilayer composite yoga mat 1 comprises the following steps:

1) preparation of PP/EPDM masterbatch

2) preparation of POE foamed substrate

b. mixing 10 parts of mixed low-density polyethylene with a foaming agent and a modifier at high speed at normal temperature, and then carrying out banburying extrusion granulation to obtain modified foaming master batches;

c. mixing 5 parts of mixed low-density polyethylene and a compound antioxidant at high speed at normal temperature, and then carrying out banburying extrusion granulation to obtain antioxidant master batches;

3) preparation of polyethylene foamed substrate

b. mixing 40 parts of polyethylene, a foaming agent and a modifier at high speed at normal temperature, and then carrying out banburying extrusion granulation to obtain modified foaming master batches;

c. mixing 20 parts of polyethylene and a composite antioxidant at high speed at normal temperature, and then carrying out banburying extrusion granulation to obtain antioxidant master batches;

4) integral subsequent processing

c. finally, performing free foaming on the polyethylene foaming master slice at a foaming temperature of 260-330 ℃ to obtain a PE foaming sheet, adhering the PE foaming sheet on a double-layer composite sheet by using an adhesive, cutting edges and rolling to obtain the multilayer composite yoga mat 1, wherein the multilayer composite yoga mat 1 sequentially comprises a polyethylene foaming layer, a POE foaming layer and a PP/EPDM substrate from top to bottom;

example 2

The multilayer composite yoga mat 2 comprises a polyethylene foaming layer, a POE foaming layer and a PP/EPDM substrate from top to bottom in sequence, wherein,

the PP/EPDM substrate comprises, by weight, 30 parts of homopolymerized polypropylene, 70 parts of ethylene propylene diene monomer EPDM, 1.6 parts of dicumyl peroxide (DCP), 1 part of phenolic resin, 5 parts of pentaerythritol triacrylate, 2 parts of a compound antioxidant and 1 part of activated carbon;

wherein, in the compound antioxidant, the weight ratio of the antioxidant 1010 to the antioxidant DSTP is 2: 1;

the POE foaming layer comprises, by weight, 70 parts of POE, 10 parts of mixed low-density polyethylene, 10 parts of EVA (ethylene-vinyl acetate copolymer), 1 part of POE foaming agent, 2 parts of zinc acetate and 0.5 part of composite antioxidant;

wherein the mixed low-density polyethylene is prepared by mixing low-density polyethylene and linear low-density polyethylene according to the weight ratio of 2: 1

In the compound antioxidant, the weight ratio of the antioxidant PKY-168 to the antioxidant DSTP is 2: 1

The POE layer foaming agent is a compound foaming agent, wherein in the compound foaming agent, the weight ratio of azodicarbonamide, sodium bicarbonate and citric acid is 12: 1;

the polyethylene foaming layer comprises, by weight, 90 parts of low-density polyethylene, 10 parts of ethylene-vinyl acetate copolymerized EVA, 10 parts of PE layer foaming agent, 2 parts of zinc stearate, 0.5 part of composite antioxidant, 1 part of diatomite and 0.3 part of succinic acid.

Wherein, in the PE layer foaming agent, the weight ratio of azodicarbonamide, sodium bicarbonate and citric acid is 12: 2: 1;

in the compound antioxidant, the weight ratio of the antioxidant PKY-168 to the antioxidant DSTP is 2: 1.

1) preparation of PP/EPDM masterbatch

2) preparation of POE foamed substrate

b. mixing 5 parts of mixed low-density polyethylene with a foaming agent and a modifier at high speed at normal temperature, and then carrying out banburying extrusion granulation to obtain modified foaming master batches;

d. mixing the modified foaming agent master batch, the antioxidant master batch, ethylene-vinyl acetate copolymer EVA and ethylene-octene copolymer POE, and extruding into sheets by using an extruder to obtain POE foamed substrates;

3) preparation of polyethylene foamed substrate

b. mixing 30 parts of polyethylene, a foaming agent and a modifier at a high speed at normal temperature, and then carrying out banburying extrusion granulation to obtain modified foaming master batches;

c. mixing 30 parts of polyethylene and a composite antioxidant at high speed at normal temperature, and then carrying out banburying extrusion granulation to obtain antioxidant master batches;

4) integral subsequent processing

c. and finally, carrying out free foaming on the polyethylene foaming master slice at a foaming temperature of 260-330 ℃ to obtain a PE foaming sheet, gluing and attaching the PE foaming sheet on a double-layer composite sheet, cutting edges and rolling to obtain the multilayer composite yoga mat 2, wherein the multilayer composite yoga mat 2 sequentially comprises a polyethylene foaming layer, a POE foaming layer and a PP/EPDM substrate from top to bottom.

Example 3

This example is substantially the same as example 1 except that:

the multilayer composite yoga mat 3 comprises a polyethylene foaming layer, a POE foaming layer and a PP/EPDM substrate from top to bottom in sequence, wherein,

the PP/EPDM substrate comprises 60 parts of polypropylene resin PP, 40 parts of ethylene propylene diene monomer EPDM, 1.0 part of dicumyl peroxide DCP, 3 parts of sulfur, 5 parts of trimethylolpropane triacrylate, 0.5 part of compound antioxidant and 2 parts of activated carbon;

wherein the polypropylene resin PP consists of homopolymerized polypropylene and block copolymerization polypropylene according to the weight ratio of 1: 1;

the weight ratio of the composite antioxidant 1010 to the antioxidant SKY-1035 is 1: 1;

the POE foaming layer comprises the following raw materials, by weight, 90 parts of POE, 10 parts of mixed low-density polyethylene, 6 parts of EVA (ethylene-vinyl acetate copolymer), 4 parts of AIBN (azodiisobutyronitrile), 0.5 part of zinc carbonate and 1 part of a composite antioxidant;

wherein the mixed low-density polyethylene is prepared by mixing low-density polyethylene and linear low-density polyethylene according to the weight ratio of 1: 1,

the weight ratio of the antioxidant 1076 to the antioxidant PKY-168 is 8: 1;

the polyethylene foaming layer comprises, by weight, 70 parts of polyethylene, 20 parts of ethylene-vinyl acetate copolymerized EVA, 5 parts of 4, 4-oxo-bis (sulfonyl hydrazide) OBSH, 1.5 parts of PE layer modifier, 1 part of compound antioxidant, 2 parts of diatomite and 0.1 part of (4-hydroxy-2, 2,6, 6-tetramethyl-1-piperidinol) and bis (2, 2,6, 6-tetramethyl-4-hydroxypiperidine) sebacate;

wherein the polyethylene consists of low density polyethylene and linear low density polyethylene according to the weight ratio of 1: 1,

in the PE layer foaming agent, the weight ratio of azodicarbonamide, sodium bicarbonate and citric acid is 16: 1;

the compound antioxidant is composed of antioxidant 1076 and antioxidant 168 with the weight ratio of 4: 1.

Example 4

This example is essentially the same as example 1 except that:

the multilayer composite yoga mat 4 comprises a polyethylene foaming layer, a POE foaming layer and a PP/EPDM substrate from top to bottom in sequence, wherein,

the PP/EPDM substrate comprises, by weight, 40 parts of polypropylene resin PP, 50 parts of ethylene propylene diene monomer EPDM, 1.2 parts of dicumyl peroxide (DCP), 3 parts of a vulcanizing agent, 7 parts of an auxiliary crosslinking agent, 1.0 part of a compound antioxidant and 1-2 parts of activated carbon;

wherein in the polypropylene resin PP, the weight ratio of the homopolymerized polypropylene to the block copolymerized polypropylene to the random copolymerized polypropylene is 1: 4: 10;

the vulcanizing agent consists of sulfur and phenolic resin, wherein the weight ratio of the sulfur to the phenolic resin is 1: 3;

the auxiliary crosslinking agent consists of pentaerythritol triacrylate and trimethylolpropane triacrylate, wherein the weight ratio of the pentaerythritol triacrylate to the trimethylolpropane triacrylate is 1: 2;

the compound antioxidant consists of an antioxidant 1010, an antioxidant DSTP and an antioxidant SKY-1035 according to the weight ratio of 3: 1: 2;

the POE foaming layer comprises raw materials of, by weight, 80 parts of POE, 20 parts of mixed low-density polyethylene, 8 parts of EVA (ethylene-vinyl acetate copolymer), 5 parts of POE foaming agent, 1.0 part of POE modifying agent and 1.2 parts of composite antioxidant;

in the POE foaming layer, low-density polyethylene is formed by blending low-density polyethylene and linear low-density polyethylene, and the weight ratio of the low-density polyethylene to the linear low-density polyethylene is 2: 1;

in the POE layer modifier, the weight ratio of zinc acetate to zinc carbonate is 1: 3;

the compound antioxidant consists of an antioxidant 1076, an antioxidant JC-242 and an antioxidant PKY-168 according to the weight ratio of 8: 1;

the polyethylene foaming layer comprises, by weight, 80 parts of polyethylene, 15 parts of ethylene-vinyl acetate copolymer (EVA), 6 parts of PE layer foaming agent, 0.8 part of PE layer modifier, 1.2 parts of composite antioxidant, 1.2 parts of diatomite and 0.04 part of succinic acid.

In the polyethylene foaming layer, the polyethylene is formed by blending low-density polyethylene, linear low-density polyethylene and high-density polyethylene, and the weight ratio of the low-density polyethylene to the linear low-density polyethylene to the high-density polyethylene is 12: 2: 1

In the PE layer foaming agent, the weight ratio of azodicarbonamide, sodium bicarbonate and citric acid is 12: 2: 1;

in the PE layer modifier, the weight ratio of zinc stearate to zinc oxide is 1: 1.

The compound antioxidant is composed of an antioxidant 1076 and an antioxidant 168 according to the weight ratio of 4: 1.

Example 5

The preparation method of this example is substantially the same as that of example 1 except that:

the multilayer composite yoga mat 5 comprises a polyethylene foaming layer, a POE foaming layer and a PP/EPDM substrate from top to bottom in sequence, wherein,

the PP/EPDM substrate comprises, by weight, 40 parts of polypropylene resin PP, 50 parts of ethylene propylene diene monomer EPDM, 1.2 parts of dicumyl peroxide (DCP), 4 parts of a vulcanizing agent, 8 parts of an auxiliary crosslinking agent, 1 part of a compound antioxidant and 1 part of activated carbon;

in the polypropylene resin PP, the weight ratio of the homopolymerized polypropylene to the block copolymerized polypropylene to the random copolymerized polypropylene is 1: 4: 8;

the auxiliary crosslinking agent consists of pentaerythritol triacrylate and trimethylolpropane triacrylate, wherein the weight ratio of the pentaerythritol triacrylate to the trimethylolpropane triacrylate is 1: 1.

The compound antioxidant consists of an antioxidant 1010 and an antioxidant DSTP according to the weight ratio of 5: 1;

the POE foaming layer comprises raw materials of, by weight, 80 parts of POE, 20 parts of mixed low-density polyethylene, 8 parts of EVA (ethylene-vinyl acetate copolymer), 4 parts of POE foaming agent, 0.8 part of POE modifying agent and 1.4 parts of composite antioxidant;

the mixed low-density polyethylene is formed by blending low-density polyethylene and linear low-density polyethylene, and the weight ratio of the low-density polyethylene to the linear low-density polyethylene is 2: 1;

in the POE layer foaming agent, the weight ratio of azodicarbonamide, sodium bicarbonate and citric acid is 12: 1;

the compound antioxidant is prepared by an antioxidant 1076, an antioxidant JC-242 and an antioxidant PKY-168 according to the weight ratio of 8: 2: 1;

the polyethylene foaming layer comprises, by weight, 80 parts of polyethylene, 15 parts of ethylene-vinyl acetate copolymer (EVA), 6 parts of PE layer foaming agent, 1.0 part of PE layer modifier, 1.5 parts of compound antioxidant, 1.8 parts of diatomite and 0.07-0.3 part of nitrilotris [ 2,2,6, 6-tetramethyl-4-hydroxypiperidine) acetate ].

The polyethylene in the polyethylene foaming layer is formed by blending low-density polyethylene, linear low-density polyethylene and high-density polyethylene, and the weight ratio of the low-density polyethylene to the linear low-density polyethylene to the high-density polyethylene is 13: 2: 1

In the PE layer foaming agent compound type foaming agent, the weight ratio of azodicarbonamide, sodium bicarbonate and citric acid is 14: 2: 1;

in the PE layer modifier, the weight ratio of zinc stearate to zinc oxide is 2: 1.

The weight ratio of the antioxidant 1076 to the antioxidant 168 of the compound antioxidant is 4: 1.

Example 6

the multilayer composite yoga mat 6 comprises a polyethylene foaming layer, a POE foaming layer and a PP/EPDM substrate from top to bottom in sequence, wherein,

the PP/EPDM substrate comprises, by weight, 40 parts of polypropylene resin PP, 60 parts of ethylene propylene diene monomer EPDM, 1.2 parts of dicumyl peroxide (DCP), 5 parts of phenolic resin, 6 parts of trimethylolpropane triacrylate, 1.2 parts of a compound antioxidant and 1 part of activated carbon;

in the polypropylene resin PP, the weight ratio of block copolymerization polypropylene to random copolymerization polypropylene is 1: 1;

the POE foaming layer comprises raw materials of, by weight, 80 parts of POE, 15 parts of mixed low-density polyethylene, 6 parts of EVA (ethylene-vinyl acetate copolymer), 4 parts of POE foaming agent, 1.2 parts of POE modifying agent and 1 part of composite antioxidant;

in the POE foaming layer, the low-density polyethylene consists of low-density polyethylene and linear low-density polyethylene according to the weight ratio of 2: 1;

in the compound type foaming agent, the weight ratio of azodicarbonamide, sodium bicarbonate and citric acid is 16: 2: 1;

the polyethylene foaming layer comprises, by weight, 80 parts of polyethylene, 18 parts of ethylene-vinyl acetate copolymer (EVA), 10 parts of PE layer foaming agent, 0.5 part of PE layer modifier, 0.5 part of composite antioxidant, 2 parts of diatomite and 0.2 part of succinic acid.

In the polyethylene foaming layer, polyethylene is formed by blending low-density polyethylene, linear low-density polyethylene and high-density polyethylene, and the weight ratio of the low-density polyethylene to the linear low-density polyethylene to the high-density polyethylene is 13: 2: 1

The compound antioxidant is composed of an antioxidant 1076 and an antioxidant 168 according to the weight ratio of 3: 1.

Example 7

The preparation method of this example is substantially the same as that of example 2 except that:

the multilayer composite yoga mat 7 comprises a polyethylene foaming layer, a POE foaming layer and a PP/EPDM substrate from top to bottom in sequence, wherein,

the PP/EPDM substrate comprises, by weight, 50 parts of polypropylene resin PP, 60 parts of ethylene propylene diene monomer EPDM, 0.9 part of dicumyl peroxide (DCP), 2 parts of a vulcanizing agent, 7 parts of an auxiliary crosslinking agent, 0.8 part of a compound antioxidant and 1 part of activated carbon;

in the polypropylene resin PP, the weight ratio of the homopolymerized polypropylene to the block copolymerized polypropylene to the random copolymerized polypropylene is 1: 3: 10;

the auxiliary crosslinking agent consists of pentaerythritol triacrylate and trimethylolpropane triacrylate, wherein the weight ratio of the pentaerythritol triacrylate to the trimethylolpropane triacrylate is 1: 2.

The compound antioxidant consists of an antioxidant 1010, an antioxidant DSTP and an antioxidant SKY-1035 according to the weight ratio of 5: 1: 2;

the POE foaming layer comprises, by weight, 70 parts of POE, 20 parts of mixed low-density polyethylene, 8 parts of ethylene-vinyl acetate copolymerized EVA, 3 parts of POE foaming agent, 0.8 part of POE layer modifier and 0.8 part of composite antioxidant;

the POE foaming layer is characterized in that the low-density polyethylene in the POE foaming layer is formed by blending low-density polyethylene and linear low-density polyethylene, and the weight ratio of the low-density polyethylene to the linear low-density polyethylene is 2: 1;

in the compound type foaming agent, the weight ratio of azodicarbonamide, sodium bicarbonate and citric acid is 14: 2: 1;

the compound antioxidant consists of an antioxidant 1076, an antioxidant JC-242 and an antioxidant PKY-168 in a weight ratio of 8: 1;

the polyethylene foaming layer comprises 80 parts of polyethylene, 15 parts of ethylene-vinyl acetate copolymerized EVA, 2 parts of PE layer foaming agent, 0.5 part of PE layer modifier, 1.5 parts of compound antioxidant, 2 parts of diatomite, 0.2 part of (4-hydroxy-2, 2,6, 6-tetramethyl-1-piperidinol) and bis (2, 2,6, 6-tetramethyl-4-hydroxypiperidine) sebacate

In the polyethylene foaming layer, polyethylene is formed by blending low-density polyethylene, linear low-density polyethylene and high-density polyethylene, and the weight ratio of the low-density polyethylene to the linear low-density polyethylene to the high-density polyethylene is 12: 2: 1

Example 8

the multilayer composite yoga mat 8 comprises a polyethylene foaming layer, a POE foaming layer and a PP/EPDM substrate from top to bottom in sequence, wherein,

the PP/EPDM substrate comprises, by weight, 50 parts of polypropylene resin PP, 50 parts of ethylene propylene diene monomer EPDM, 0.9 part of dicumyl peroxide (DCP), 2 parts of a vulcanizing agent, 6 parts of an auxiliary crosslinking agent, 1 part of a compound antioxidant and 2 parts of activated carbon;

The compound antioxidant is prepared by antioxidant 1010, antioxidant DSTP and antioxidant SKY-1035 according to the weight ratio of 5: 1: 2;

the POE foaming layer comprises raw materials of, by weight, 80 parts of POE, 15 parts of mixed low-density polyethylene, 7 parts of EVA (ethylene-vinyl acetate copolymer), 4 parts of POE foaming agent, 0.6 part of POE modifying agent and 2 parts of composite antioxidant;

the low-density polyethylene in the POE foaming layer is formed by blending low-density polyethylene and linear low-density polyethylene, and the weight ratio of the low-density polyethylene to the linear low-density polyethylene is 2: 1;

in the POE layer modifier, the weight ratio of zinc acetate to zinc carbonate is 1: 3; the compound antioxidant is prepared by an antioxidant 1076, an antioxidant JC-242 and an antioxidant PKY-168 according to the weight ratio of 8: 1;

the polyethylene foaming layer comprises, by weight, 80 parts of polyethylene, 15 parts of ethylene-vinyl acetate copolymer (EVA), 2 parts of a PE layer foaming agent, 1 part of a PE layer modifier, 1.2 parts of a compound antioxidant, 1.5 parts of diatomite, and 0.2 part of (4-hydroxy-2, 2,6, 6-tetramethyl-1-piperidinol) and bis (2, 2,6, 6-tetramethyl-4-hydroxypiperidine) sebacate.

In the compound type foaming agent, the weight ratio of azodicarbonamide, sodium bicarbonate and citric acid is 12-16: 1-2: 1;

The weight ratio of the antioxidant 1076 to the antioxidant 168 of the compound antioxidant is 3: 1.

Example 9

the multilayer composite yoga mat 9 comprises a polyethylene foaming layer, a POE foaming layer and a PP/EPDM substrate from top to bottom in sequence, wherein,

the PP/EPDM substrate comprises, by weight, 45 parts of polypropylene resin PP, 55 parts of ethylene propylene diene monomer EPDM, 1.2 parts of dicumyl peroxide (DCP), 2 parts of a vulcanizing agent, 7 parts of an auxiliary crosslinking agent, 0.8 part of a compound antioxidant and 2 parts of activated carbon;

in the polypropylene resin PP, the weight ratio of the homopolymerized polypropylene to the block copolymerized polypropylene to the random copolymerized polypropylene is 1: 6: 11;

the compound antioxidant is prepared by antioxidant 1010, antioxidant DSTP and antioxidant SKY-1035 according to the weight ratio of 2: 1: 2;

the POE foaming layer comprises the following raw materials, by weight, 75 parts of POE, 20 parts of mixed low-density polyethylene, 8 parts of EVA (ethylene-vinyl acetate copolymer), 3 parts of POE foaming agent, 0.8 part of POE layer modifier and 1 part of composite antioxidant;

the POE foaming layer is characterized in that the low-density polyethylene in the POE foaming layer is formed by blending low-density polyethylene and linear low-density polyethylene, and the weight ratio of the low-density polyethylene to the linear low-density polyethylene is 3: 1;

in the POE layer modifier, the weight ratio of zinc acetate to zinc carbonate is 1: 4;

in the POE foaming layer, the compound antioxidant consists of hindered phenol antioxidant and phosphite antioxidant, and consists of n-octadecyl beta- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate (antioxidant 1076), bis (2, 4-di-tert-butylphenyl) (antioxidant JC-242) and tris (2, 4-di-tert-butyl) phenyl phosphite (antioxidant PKY-168); wherein the weight ratio of the antioxidant 1076, the antioxidant JC-242 and the antioxidant PKY-168 is 8: 1;

the polyethylene foaming layer comprises, by weight, 78 parts of polyethylene, 15-20 parts of ethylene-vinyl acetate copolymerized EVA, 2 parts of PE layer foaming agent, 1 part of PE layer modifier, 1.2 parts of compound antioxidant, 1.5 parts of diatomite, and 0.2 part of (4-hydroxy-2, 2,6, 6-tetramethyl-1-piperidinol) and bis (2, 2,6, 6-tetramethyl-4-hydroxypiperidine) sebacate.

The polyethylene in the polyethylene foaming layer is formed by blending low-density polyethylene, linear low-density polyethylene and high-density polyethylene, and the weight ratio of the low-density polyethylene to the linear low-density polyethylene to the high-density polyethylene is 16: 3: 1

In the compound type foaming agent, the weight ratio of azodicarbonamide, sodium bicarbonate and citric acid is 12: 2: 1;

The compound antioxidant is prepared from an antioxidant 1076 and an antioxidant 168 in a weight ratio of 2: 1.

The performance of the multi-layer composite yoga mat prepared in the above examples 1 to 9 was compared

Note: comparative example 1 is the yoga mat disclosed in patent publication No. CN104307136A, and comparative example 2 is the yoga mat disclosed in patent publication No. CN 103205074A.

Comparative example 1 yoga mat was prepared only with different EVA foam materials, with shore hardness value between 30-45, without the advantages of impact strength, resilience and tactile sensation. The invention adopts PP/EPDM as the substrate, thereby improving the toughness and the impact strength of the material, simultaneously increasing the friction force of the yoga mat to the ground when in use, playing a role of skid resistance, having the Shore hardness value of 40-60A and the notch impact degree of 65kJ/m². The intermediate layer is made of POE (polyolefin elastomer) foaming materials, the hardness value is 30-40A, good resilience can be achieved, and the resilience can reach 50-85%. The surface layer is made of PE foaming materials, the hardness value is 25-30A, and the yoga mat has a good touch feeling.

Comparative example 2 only adopts a layer of expanded material as the yoga mat, and the hardness number reaches 54A, and the resilience 20%, neither comfortable had, and the resilience is poor simultaneously, and impact strength is poor. The resilience of the yoga mat prepared in this example is much higher than that of the yoga mat of comparative example 2; and example 1 the yoga mat prepared has the highest resilience.

Other parts not described in detail are prior art. Although the present invention has been described in detail with reference to the above embodiments, it is only a part of the embodiments of the present invention, not all of the embodiments, and other embodiments can be obtained without inventive step according to the embodiments, and the embodiments are within the scope of the present invention.

Claims

1. The utility model provides a compound yoga mat of multilayer which characterized in that: the multilayer composite yoga mat sequentially comprises a polyethylene foaming layer, a POE foaming layer and a PP/EPDM substrate from top to bottom, wherein,

the PP/EPDM substrate comprises, by weight, 30-60 parts of polypropylene resin, 40-70 parts of ethylene propylene diene monomer, 0.9-1.6 parts of dicumyl peroxide, 1-5 parts of a vulcanizing agent, 5-10 parts of an auxiliary crosslinking agent, 0.5-2 parts of a composite antioxidant and 1-2 parts of activated carbon;

the POE foaming layer comprises, by weight, 70-90 parts of ethylene-octene copolymer, 10-30 parts of mixed low-density polyethylene, 5-10 parts of ethylene-vinyl acetate copolymer, 1-10 parts of POE layer foaming agent, 0.1-2 parts of POE layer modifier and 0.5-2 parts of composite antioxidant;

the polyethylene foaming layer comprises, by weight, 70-90 parts of polyethylene, 10-20 parts of ethylene-vinyl acetate copolymer, 1-10 parts of PE layer foaming agent, 0.1-2 parts of PE layer modifier, 0.5-2 parts of composite antioxidant, 1-2 parts of diatomite and 0.07-0.3 part of hindered amine light stabilizer.

2. The multi-layer composite yoga mat of claim 1, wherein:

the PP/EPDM substrate comprises, by weight, 40-50 parts of polypropylene resin, 50-60 parts of ethylene propylene diene monomer, 0.9-1.6 parts of dicumyl peroxide, 2-3 parts of a vulcanizing agent, 6-8 parts of an auxiliary crosslinking agent, 0.5-1 part of a composite antioxidant and 1-2 parts of activated carbon;

the POE foaming layer comprises, by weight, 70-80 parts of ethylene-octene copolymer, 15-25 parts of mixed low-density polyethylene, 7-9 parts of ethylene-vinyl acetate copolymer, 2-4 parts of POE layer foaming agent, 0.6-1 part of POE layer modifier and 1-2 parts of composite antioxidant;

the polyethylene foaming layer comprises, by weight, 75-80 parts of polyethylene, 15-20 parts of ethylene-vinyl acetate copolymer, 2-3 parts of PE layer foaming agent, 0.1-2 parts of PE layer modifier, 0.5-2 parts of composite antioxidant, 1-2 parts of diatomite and 0.1-0.3 part of hindered amine light stabilizer.

3. The multi-layer composite yoga mat of claim 1 or 2, wherein:

the polypropylene resin is selected from homo-polypropylene, block co-polypropylene and random co-polypropylene; wherein the melting temperature of the polypropylene resin is 145-195 ℃, and the melt flow rate is 1.0-3.0 g/10 min;

the vulcanizing agent is selected from phenolic resin and sulfur;

the POE layer foaming agent is a compound foaming agent or azodiisobutyronitrile, wherein the compound foaming agent is composed of azodicarbonamide, sodium bicarbonate and citric acid;

the POE layer modifier is selected from zinc acetate and zinc carbonate;

the PE layer modifier is selected from zinc stearate and zinc oxide;

the hindered amine light stabilizer is selected from succinic acid, 4-hydroxy-2, 2,6, 6-tetramethyl-1-piperidinol, bis (2, 2,6, 6-tetramethyl-4-hydroxypiperidine) sebacate, and nitrilotris [ acetic acid (2, 2,6, 6-tetramethyl-4-hydroxypiperidine) ester ].

4. The multi-layer composite yoga mat of claim 1 or 2, wherein:

in the polypropylene resin PP, the weight ratio of the homopolymerized polypropylene to the block copolymerized polypropylene to the random copolymerized polypropylene is 1: 2-7: 5-11;

5. The multi-layer composite yoga mat of claim 1 or 2, wherein:

in the POE foaming layer, low-density polyethylene is formed by blending low-density polyethylene and linear low-density polyethylene, and the weight ratio of the low-density polyethylene to the linear low-density polyethylene is 1-3: 1;

in the polyethylene foaming layer, polyethylene is formed by blending low-density polyethylene, linear low-density polyethylene and high-density polyethylene, and the weight ratio of the low-density polyethylene to the linear low-density polyethylene to the high-density polyethylene is 12-16: 1-3: 1

6. The multi-layer composite yoga mat of claim 1 or 2, wherein:

the compound antioxidant consists of hindered phenol antioxidant and thioester antioxidant/phosphite antioxidant, wherein,

the hindered phenol antioxidants are pentaerythrityl tetrakis [ beta- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate ], n-octadecyl beta- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate and 2, 2' -thiobis [3- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate ];

the thioester antioxidant is distearyl thiodipropionate;

the phosphite antioxidant is selected from tris (2, 4-di-tert-butyl) phenyl phosphite and bis (2, 4-di-tert-butylphenyl) pentaerythritol diphosphite.

7. The multi-layer composite yoga mat of claim 6, wherein:

in the PP/EPDM substrate, the compound antioxidant consists of hindered phenol antioxidants and thioester antioxidants, and consists of tetra [ beta- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionic acid ] pentaerythritol ester, distearyl thiodipropionate and 2, 2' -thiobis [3- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate ]; pentaerythritol tetrakis [ beta- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate ], distearyl thiodipropionate serving as an antioxidant and 2, 2' -thiobis [3- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate ] in a weight ratio of 2-5: 1: 2-5;

in the POE foaming layer, the compound antioxidant consists of hindered phenol antioxidant and phosphite antioxidant, and consists of n-octadecyl beta- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate, bis (2, 4-di-tert-butylphenyl) pentaerythritol diphosphite and tris (2, 4-di-tert-butyl) phenyl phosphite; wherein the weight ratio of the n-octadecyl beta- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate to the bis (2, 4-di-tert-butylphenyl) pentaerythritol diphosphite to the tris (2, 4-di-tert-butyl) phenyl phosphite is 7-9: 1-2: 1;

in the polyethylene foaming layer, the composite antioxidant consists of hindered phenol antioxidant and phosphite antioxidant, and consists of n-octadecyl beta- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate and phenyl tri (2, 4-di-tert-butyl) phosphite; wherein the weight ratio of the n-octadecyl beta- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate to the tris (2, 4-di-tert-butyl) phenyl phosphite is 2-5: 1.

8. The multi-layer composite yoga mat of claim 1 or 2, wherein:

the multilayer composite yoga mat sequentially comprises a polyethylene foaming layer, a POE foaming layer and a PP/EPDM substrate from top to bottom, wherein,

the PP/EPDM substrate comprises, by weight, 60 parts of polypropylene resin, 40 parts of ethylene propylene diene monomer, 1.5 parts of dicumyl peroxide, 2 parts of a vulcanizing agent, 6 parts of an auxiliary crosslinking agent, 0.8 part of a composite antioxidant and 1.2 parts of activated carbon; wherein the content of the first and second substances,

the polypropylene resin consists of homopolymerized polypropylene, block copolymerized polypropylene and random copolymerized polypropylene, wherein the weight ratio of the homopolymerized polypropylene to the block copolymerized polypropylene to the random copolymerized polypropylene is 1: 3: 6;

the compound antioxidant consists of tetra [ beta- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionic acid ] pentaerythritol ester, thiodipropionic acid distearyl ester and 2, 2' -thiobis [3- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionate ] according to the weight ratio of 3: 1: 3;

the POE foaming layer comprises 80 parts of ethylene-octene copolymer, 20 parts of mixed low-density polyethylene, 6 parts of ethylene-vinyl acetate copolymer, 3 parts of POE layer foaming agent, 1 part of POE layer modifier and 0.8 part of composite antioxidant in parts by weight;

the polyethylene foaming layer comprises 80 parts of polyethylene, 15 parts of ethylene-vinyl acetate copolymer (EVA), 2 parts of PE layer foaming agent, 0.5 part of PE layer modifier, 1 part of composite antioxidant, 1.2 parts of diatomite and 0.2 part of hindered amine light stabilizer by weight;

in the polyethylene foam layer,

the polyethylene is prepared by blending low density polyethylene, linear low density polyethylene and high density polyethylene, wherein the weight ratio of the low density polyethylene to the linear low density polyethylene to the high density polyethylene is 13: 2: 1

9. The multi-layer composite yoga mat of claim 1 or 2, wherein: the yoga mat is 4.0-8.0 mm in thickness, wherein the polyethylene foaming layer, the POE foaming layer and the PP/EPDM substrate are 2-4 mm, 1-2 mm and 1-2 mm in thickness respectively;

the resilience of the multilayer composite yoga mat is 70-85%.