CN114043696A

CN114043696A - Wood-grain-like HDPE co-extruded foam board and preparation method thereof

Info

Publication number: CN114043696A
Application number: CN202111309744.8A
Authority: CN
Inventors: 周云; 马庆江; 周全; 张冰; 冯卓
Original assignee: Ningbo Helong New Material Co Ltd
Current assignee: Ningbo Helong New Material Co Ltd
Priority date: 2021-11-02
Filing date: 2021-11-02
Publication date: 2022-02-15

Abstract

The application relates to a wood-grain-like HDPE co-extruded foamed plate and a preparation process thereof, belonging to the field of foamed plates. The foaming core layer comprises the following raw materials: high-density polyethylene, a melt reinforcing agent, a core layer filler, a foaming agent, a foaming activator and a crosslinking agent; the surface co-extrusion layer is prepared from the following raw materials: HDPE, vinyl copolymer, polyethylene elastomer, surface layer filler and surface layer color master batch with two colors. The preparation method comprises the following steps: preparing materials; melting and foaming the core layer mixture, and cooling and pre-shaping to obtain a foamed core layer; mixing and extruding the melted surface co-extrusion materials with two different colors, and coating the surface of the foaming core layer substrate to form a surface co-extrusion layer with a wood grain imitation; and (6) cooling and shaping. The co-extruded foam board has good heat preservation and sound insulation effects, better wear resistance and surface hardness compared with the traditional foam board, more economic manufacturing cost and wider application value.

Description

Wood-grain-like HDPE co-extruded foam board and preparation method thereof

Technical Field

The invention relates to the field of foaming materials, in particular to a wood-grain-like HDPE co-extruded foaming plate and a preparation method thereof.

Background

The polyethylene foam material is a building material which is prepared by taking polypropylene resin as a main body and adding a foaming agent, a cross-linking agent and other additives, and is widely applied to the fields of filling materials, sound and heat insulation materials, building industry materials, light weight materials and the like due to the advantages of small density, chemical corrosion resistance, good heat insulation, low water absorption, low manufacturing cost and the like.

However, the polyethylene foam material is easy to foam unevenly, which causes uneven traction and tension stress when the outlet die is extruded after the foam body is foamed and expanded in the die, so that the surface of the polyethylene foam section forms an orange peel, which reduces the quality of the foamed plate.

Disclosure of Invention

In order to improve the quality and the aesthetic degree of the co-extruded foamed board, the application provides the wood-grain-like HDPE co-extruded foamed board and the preparation process thereof.

In a first aspect, the application discloses a preparation method of a wood-like HDPE co-extruded foam board, which adopts the following technical scheme:

a preparation method of a wood-like HDPE co-extruded foam board comprises the following preparation steps:

step 1) material preparation:

core layer mixture: uniformly mixing raw materials including 40-80 parts by weight of high-density polyethylene, 5.15-10.5 parts by weight of melt reinforcing agent, 10-40 parts by weight of core layer filler and 0.5-1.5 parts by weight of cross-linking agent to obtain a core layer mixture for later use; surface layer mixture: mixing, plasticizing and granulating raw materials comprising 65-90 parts by weight of HDPE, 3-5 parts by weight of vinyl copolymer, 5-10 parts by weight of polyethylene elastomer, 3-10 parts by weight of surface layer filler and 1-5 parts by weight of compatilizer to prepare surface co-extrusion layer functional particles, dividing the surface co-extrusion layer functional particles into two parts, and respectively mixing 2-3 parts by weight of surface color master batches with different colors to obtain two parts of surface layer mixture for later use;

step 2) extruding a foaming core layer:

pouring the prepared core layer mixture into a hopper of a core layer extruder for melting and plasticizing, adding 0.4-5 parts of foaming agent and 0.4-2 parts of foaming activating agent into a homogenizing section at the rear end of a screw of the core layer extruder for foaming, extruding into a core layer mold for foaming and molding, and then pre-shaping through a core layer cooling mold to obtain a foamed core layer;

step 3) surface layer co-extrusion coating:

respectively putting the prepared two surface layer mixed materials into hoppers of two surface layer extruders, respectively carrying out melting plasticization on the poured surface layer mixed materials by the two surface layer extruders to obtain surface co-extruded materials, wherein the surface co-extruded material of one surface layer extruder is converged into the other surface layer extruder through a confluence core, meanwhile, a foaming core layer passes through the center of a co-extrusion die, the melted surface co-extruded materials with two different colors are mixed and extruded to the co-extrusion die, and are coated on the surface of a foaming core layer substrate to form a wood-like patterned surface co-extruded layer;

step 4), cooling and shaping: and (4) after extrusion by the co-extrusion die, shaping by the co-extrusion cooling die to obtain the wood-grain-like HDPE co-extrusion foaming board.

The foaming core layer with good heat preservation, energy saving, sound insulation and light performance is prepared by plasticizing, foaming and cooling the high-density polyethylene, the melt reinforcing agent, the core layer filling agent, the cross-linking agent, the foaming agent and the foaming activating agent, and the foaming core layer is rapidly cooled and pre-shaped by the cooling mould before an outlet mould, so that the formation of surface orange peel of the foaming core layer in the outlet mould is reduced, and the subsequent surface co-extrusion layer can be better co-extruded and coated; in addition, the HDPE, the vinyl copolymer, the polyethylene elastomer, the surface layer filler and the compatilizer are adopted for plasticizing granulation to prepare the surface co-extrusion layer functional particles, and the surface co-extrusion layer functional particles are mixed and plasticized with the color master batches with different colors, so that the color of the two plasticized and melted surface co-extrusion materials is more controllable, and the color development condition of the color master batches is not easily influenced due to overlong plasticizing time, so that the surface co-extrusion layer is co-extruded and coated on the surface of the foaming core layer to form a more natural and attractive wood-like pattern; according to the application, the surface co-extrusion layer is coated on the surface of the foaming core layer by adopting a co-extrusion coating technology, so that the problems of low surface hardness and low wear resistance of the existing polyethylene foaming plate can be solved, compared with the original pure non-foaming plate, the co-extrusion foaming plate reduces the manufacturing cost, greatly improves the performances of sound insulation, heat insulation, light shock resistance and the like, and can form a natural wood texture effect on the surface of the plate, thereby being widely applied to the field of building materials.

Preferably, the melt reinforcing agent comprises: 0.15-0.5 part of coated polytetrafluoroethylene particles and 5-10 parts of ultrahigh molecular weight polyethylene.

Preferably, the coated polytetrafluoroethylene particles are shell-core structured particles having a shell of one or more monomers of ethylene, propylene, butadiene, acrylic acid and methacrylic acid and a core of polytetrafluoroethylene, and have a particle diameter of 0.05 to 1 mm. The molecular weight of the ultra-high molecular weight polyethylene is 200-500 ten thousand.

Through adopting cladding type polytetrafluoroethylene particle and ultra high molecular polyethylene as the fuse-element reinforcing agent of foaming sandwich layer, cladding type polytetrafluoroethylene particle has better dispersibility and anti pyrolysis nature because the shell cladding on its surface, thereby make polytetrafluoroethylene have better intensity improvement effect to the foaming sandwich layer, and combine a certain amount of ultra high molecular polyethylene to cooperate jointly, can make the foaming sandwich layer have good fuse-element tension and mobility when the plastify, be favorable to the even foaming of foaming sandwich layer, thereby improve the overall structure intensity of foaming sandwich layer.

Preferably, the core layer filler is one or a combination of talcum powder and light calcium carbonate.

By adopting the core layer filler, the foaming core layer has certain hardness, so that the co-extruded foaming plate has more excellent overall structure stability.

Preferably, the core layer mixture further comprises 1-2 parts of a dispersing agent, wherein the dispersing agent is one or a combination of stearic acid, zinc stearate and calcium stearate.

The dispersing agent, the high-density polyethylene, the melt reinforcing agent and the core layer filler are plasticized and melted uniformly, so that the subsequent foaming agent and the foaming activating agent are dispersed better, the foaming of the foaming core layer is more uniform, the overall strength of the foaming core layer is further improved, the formation of orange peel is reduced, and the surface co-extrusion layer can be better coated and bonded on the surface of the foaming core layer.

Preferably, the crosslinking agent is one or more of a TAC crosslinking agent, a TAIC crosslinking agent and a DCP crosslinking agent.

By adopting the cross-linking agent, the system of the core layer mixture after melting and plasticizing is further cross-linked and copolymerized, so that the formed cell structure is stabilized in the foaming process, and the mechanical property and the heat insulation property of the foaming core layer are improved.

Preferably, the foaming agent is one or more of sodium bicarbonate and azodicarbonamide, and the foaming activator is zinc oxide.

By adopting the foaming agent and the foaming activating agent to foam after melting the core layer mixture containing high-density polyethylene, a melt reinforcing agent, a core layer filling agent and the like, the foaming core layer has better foam cell nucleation activity, the density of the plate is reduced, and the plate has good heat insulation and sound insulation properties.

Preferably, the polyethylene-based elastomer is a composition of one or more of POE, TPO and EVA.

Through the raw materials that adopts above polyethylene base elastomer as the surperficial crowded layer altogether, when making the function particle melting plastify of the crowded layer of crowded layer altogether of surface extrude, can cladding on the foaming sandwich layer surface better, the top layer that leads to because of the difference of foaming sandwich layer and the crowded layer expansion ratio of crowded layer altogether is separated from the phenomenon on surface has been reduced, thereby it is better to make the cohesiveness between foaming sandwich layer and the crowded layer altogether of surface, the durability is better, in addition, polyethylene base elastomer can improve the toughness of panel, thereby it has better shock resistance when panel receives the exogenic action.

Preferably, the vinyl copolymer is a combination of one or more of EAA, EEA, EMAA.

Through adopting above vinyl copolymer as the raw materials of surperficial crowded layer altogether for surperficial crowded layer altogether can have the good cohesiveness to the foaming sandwich layer, has better structural integrity after crowded cladding back shaping altogether, thereby makes crowded foaming plate surface altogether level and more pleasing to the eye, and has better mechanical properties.

Preferably, the compatibilizer is maleic anhydride grafted polyethylene.

By adding the maleic anhydride grafted polyethylene compatilizer, maleic anhydride functional groups are grafted on the vinyl copolymer and the polyethylene elastomer, so that the compatibility of the surface filler in the surface co-extruded material is enhanced, the surface filler can be better dispersed in the molten surface co-extruded material, and the effects of improving the surface strength and the wear resistance of the co-extruded foam board are better achieved.

Preferably, the surface layer filler is one or a combination of hollow glass beads, fumed silica and talcum powder.

Through adopting above surface layer filler for the roughness of surface coextrusion layer has certain improvement, increases the diffuse reflection of coextruding the foaming board surface, and then reduces the glossiness, makes coextruding the foaming board surface and presents the matte state, more has natural grain feel.

Preferably, the head of one surface layer extruder is connected to one third of the barrel of the other surface layer extruder close to the hopper through a confluence core.

Through connecting preceding surface extruder in the suitable position of back surface extruder barrel, be favorable to making the surface coextrusion material of two kinds of different colours mix the back, extrude the cladding and form the line that is close to natural timber more when foaming sandwich layer surface.

In a second aspect, the application discloses a wood-like HDPE co-extruded foam board, which adopts the following technical scheme:

the wood-grain-like HDPE co-extruded foam board is prepared by the preparation method of the wood-grain-like HDPE co-extruded foam board.

The co-extrusion foaming plate formed by the surface co-extrusion layer is coated on the surface of the foaming core layer in a co-extrusion mode, so that the wear resistance and the impact resistance of the single foaming plate can be improved, the surface co-extrusion layer with natural wood grains can be formed on the surface of the foaming core layer, the co-extrusion foaming plate has the heat insulation, sound insulation and light characteristics of the foaming plate, the good mechanical performance of a non-porous plate and the wider application value.

In a third aspect, the application discloses a HDPE surface co-extrusion layer functional particle, which adopts the following technical scheme: the HDPE surface co-extrusion layer functional particle is prepared by the preparation method of the wood-grain-like HDPE co-extrusion foaming plate.

The surface co-extrusion layer functional particles are prepared by adopting HDPE, vinyl copolymer, polyethylene elastomer, surface filler and compatilizer for granulation, the polyethylene foaming material has better coating and bonding effects in the co-extrusion process, and the surface co-extrusion layer functional particles have excellent surface hardness and wear resistance, and are convenient for subsequent production after the functional particles are successfully plasticized and granulated, so that the requirement on co-extrusion processing equipment is lowered.

In summary, the present application includes at least one of the following beneficial technical effects:

1. by adopting a co-extrusion coating process, the surface co-extrusion layer is co-extruded and coated on the surface of the foaming core layer, and the formed co-extruded foaming plate has the advantages of energy conservation and heat preservation, sound insulation and heat insulation, light weight, high wear resistance, strong impact resistance, low manufacturing cost and the like, and has good economic value;

2. the surface co-extrusion layer functional particles are divided into two parts, and the surface color master batches with different colors are mixed to respectively carry out melting plasticization, so that the two surface co-extrusion materials with different colors are mixed and co-extruded to coat on the surface of the foaming core layer, and the co-extrusion foaming plate with natural wood textures is formed, has better aesthetic property, and can be widely applied in the field of building materials;

3. the surface co-extrusion layer functional particles prepared by adopting the granulation of the HDPE, the vinyl copolymer, the polyethylene elastomer, the surface filler and the compatilizer can ensure that the surface co-extrusion layer functional particles can have better coating bonding effect on the polyethylene foam material in a co-extrusion process, so that the co-extrusion foaming plate is not easy to separate from the surface layer due to the difference of the expansion rates of the foaming core layer and the surface co-extrusion layer, and has better durability.

Drawings

FIG. 1 is a schematic view of a co-extruded foam sheet production line of an embodiment of the present invention.

Description of reference numerals: 100. a core layer extruder; 101. cooling the die for the core layer; 200. a surface layer extruder; 201. a confluence core; 300. co-extrusion mould; 301. and (5) co-extruding and cooling the mold.

Detailed Description

The present application will be described in further detail with reference to the following drawings and examples.

Examples

Example 1

The raw materials and the adding amount of the wood-like HDPE co-extruded foam board are shown in Table 1 in detail, and referring to FIG. 1, the preparation method comprises the following steps:

step 1) material preparation:

core layer mixture: uniformly mixing high-density polyethylene, a melt reinforcing agent, a core layer filling agent, a cross-linking agent and a core layer coloring agent in foaming layer raw materials according to the proportion of table 1 to obtain a core layer mixture for later use;

surface layer mixture: mixing HDPE, vinyl copolymer, surface layer filler, compatilizer and polyethylene elastomer uniformly according to the proportion in Table 1, then carrying out melt plasticization and granulation at 200 ℃ by a granulator to obtain surface co-extrusion layer functional particles with the diameter of 2-3mm, weighing the surface co-extrusion layer functional particles according to the proportion, dividing the surface co-extrusion layer functional particles into two equal parts, and then respectively mixing equal amounts of surface color master batches with different colors to obtain two surface layer mixtures for later use;

step 2) extruding a foaming core layer:

pouring the prepared core layer mixture into a hopper of a core layer extruder 100, melting and plasticizing at 160 ℃, adding a foaming agent and a foaming activating agent into a homogenizing section at the rear end of a screw of the core layer extruder 100 according to the mixture ratio shown in the table 1, keeping the temperature at 200 ℃ for foaming, extruding into a core layer mold for foaming and molding, and then cooling to 50 ℃ through a core layer cooling mold 101 for presetting to obtain a foaming core layer;

step 3) surface layer co-extrusion coating:

respectively putting the prepared two surface layer mixed materials into hoppers of two surface layer extruders 200, wherein the machine head of one surface layer extruder 200 is connected to one third of the side, close to the hopper, of the machine barrel of the other surface layer extruder 200 through a confluence core 201, the two surface layer extruders 200 respectively carry out melting plasticization on the poured surface layer mixed materials at 210 ℃ to obtain surface coextrusion materials, the surface coextrusion materials of one surface layer extruder 200 are converged into the other surface layer extruder 200 through the confluence core 201, meanwhile, a foaming core layer passes through the center of a coextrusion die 300, the molten surface coextrusion materials with two different colors are mixed and extruded to the coextrusion die 300 to be coated on the surface of a foaming core layer matrix, and a surface coextrusion layer with wood-like patterns is formed;

step 4), cooling and shaping:

and after extrusion by the co-extrusion die, cooling to 40 ℃ by the co-extrusion cooling die 301 for shaping to obtain the wood-grain-like HDPE co-extrusion foaming plate.

Example 2

step 1) material preparation:

core layer mixture: uniformly mixing high-density polyethylene, a melt reinforcing agent, a core layer filler, a cross-linking agent, a dispersing agent and a core layer coloring agent in the foaming layer raw materials according to the proportion shown in the table 1 to obtain a core layer mixture for later use;

surface layer mixture: mixing HDPE, vinyl copolymer, surface layer filler, compatilizer and polyethylene elastomer uniformly according to the proportion in Table 1, then carrying out melt plasticization and granulation at 160 ℃ by a granulator to obtain surface co-extrusion layer functional particles with the diameter of 2-3mm, weighing the surface co-extrusion layer functional particles according to the proportion, dividing the surface co-extrusion layer functional particles into two equal parts, and then respectively mixing equal amounts of surface color master batches with different colors to obtain two surface layer mixed materials for later use;

step 2) extruding a foaming core layer:

pouring the prepared core layer mixture into a hopper of a core layer extruder 100, melting and plasticizing at 140 ℃, adding a foaming agent and a foaming activating agent into a homogenizing section at the rear end of a screw of the core layer extruder 100 according to the mixture ratio shown in the table 1, keeping the temperature at 180 ℃ for foaming, extruding into a core layer mold for foaming and molding, and then cooling to 50 ℃ through a core layer cooling mold 101 for presetting to obtain a foaming core layer;

step 3) surface layer co-extrusion coating:

respectively putting the prepared two surface layer mixed materials into hoppers of two surface layer extruders 200, wherein the machine head of one surface layer extruder 200 is connected to one third of the side, close to the hopper, of the machine barrel of the other surface layer extruder 200 through a confluence core 201, the two surface layer extruders 200 respectively carry out melting plasticization on the poured surface layer mixed materials at 190 ℃ to obtain surface coextrusion materials, the surface coextrusion materials of one surface layer extruder 200 are converged into the other surface layer extruder 200 through the confluence core 201, meanwhile, a foaming core layer passes through the center of a coextrusion die 300, the molten surface coextrusion materials with two different colors are mixed and extruded to the coextrusion die 300 to be coated on the surface of a foaming core layer matrix, and a surface coextrusion layer with wood-like patterns is formed;

step 4), cooling and shaping:

Example 3

The raw materials and the adding amount of the wood-like HDPE co-extruded foam board are shown in Table 1 in detail, and the preparation method comprises the following steps of:

step 1) material preparation:

surface layer mixture: mixing HDPE, vinyl copolymer, surface layer filler, compatilizer and polyethylene elastomer uniformly according to the proportion in Table 1, then carrying out melt plasticization and granulation at 180 ℃ by a granulator to obtain surface co-extrusion layer functional particles with the diameter of 2-3mm, weighing the surface co-extrusion layer functional particles and ultraviolet resistant master batches according to the proportion, dividing the surface co-extrusion layer functional particles and the ultraviolet resistant master batches into two equal parts, and then respectively mixing equal amounts of surface color master batches with different colors to obtain two surface layer mixed materials for later use;

step 2) extruding a foaming core layer:

pouring the prepared core layer mixture into a hopper of a core layer extruder 100, melting and plasticizing at 150 ℃, adding a foaming agent and a foaming activating agent into a homogenizing section at the rear end of a screw of the core layer extruder 100 according to the proportion shown in the table 1, keeping the temperature at 190 ℃ for foaming, extruding into a core layer mold for foaming and molding, and then cooling to 50 ℃ through a core layer cooling mold 101 for presetting to obtain a foaming core layer;

step 3) surface layer co-extrusion coating:

respectively putting the prepared two surface layer mixed materials into hoppers of two surface layer extruders 200, wherein the machine head of one surface layer extruder 200 is connected to one third of the side, close to the hopper, of the machine barrel of the other surface layer extruder 200 through a confluence core 201, the two surface layer extruders 200 respectively carry out melting plasticization on the poured surface layer mixed materials at 200 ℃ to obtain surface coextrusion materials, the surface coextrusion materials of one surface layer extruder 200 are converged into the other surface layer extruder 200 through the confluence core 201, meanwhile, a foaming core layer passes through the center of a coextrusion die 300, the molten surface coextrusion materials with two different colors are mixed and extruded to the coextrusion die 300 to be coated on the surface of a foaming core layer matrix, and a surface coextrusion layer with wood-like patterns is formed;

step 4), cooling and shaping:

Examples 4 to 6

The differences from example 3 are in the amounts of raw materials added in examples 4-6, as detailed in Table 1.

TABLE 1 raw materials and their amounts added (unit: kg) in examples 1 to 6

The raw material sources adopted in the application are all commercial products except the following special descriptions:

the high-density polyethylene and HDPE are made of YEM-4902T high-density polyethylene petrochemical from winnowing;

the coated polytetrafluoroethylene particle is a DL-155 anti-dripping agent prepared from Xinrui new materials Co., Ltd, Dongguan city, and the PTEE content is 55 percent;

the ultra-high molecular weight polyethylene is selected from GUR 4150 ultra-high molecular weight polyethylene;

the cross-linking agent is TAIC cross-linking agent of Jiangsu Runfeng synthetic science and technology limited;

the compatilizer is HDPE-g-MAH compatilizer with the mark of 40E529 of the DuPont company in the United states;

the ultraviolet resistant master batch is 2207 ultraviolet resistant master batch from German scientific institute.

Comparative example

Comparative example 1: a co-extruded foam board is different from the co-extruded foam board in the embodiment 1) in the step 1) of the comparative example 1, and a melt reinforcing agent is not added when the core layer concrete is prepared.

Comparative example 2: a coextruded foamed sheet differs from example 1 in that in step 1) of comparative example 2, equal mass HDPE is used in place of the ethylene-based copolymer in the surface coextrusion layer high energy particle granulation.

Comparative example 3: a coextruded foamed sheet differs from example 1 in that in step 1) of comparative example 3, equal mass HDPE polyethylene based elastomer is used for surface coextrusion layer high energy particle granulation.

Comparative example 4: a co-extruded foam board is different from the co-extruded foam board in the embodiment 1), in the step 1) of the comparative example 4, surface layer filling agents and compatilizers are not added during granulation of surface co-extruded layer high-energy particles.

Performance test

Detecting a sample object: the wood grain-like HDPE coextruded foam boards prepared in examples 1-6 above were used as experimental samples 1-6, and the coextruded foam boards prepared in comparative examples 1-4 were used as control samples 1-4.

Detection reference standard: according to a test method of ASTM D4060-14 standard, a Taber abrasion tester is used for testing the abrasion resistance of the sample object; according to a test method of BS EN 15534-1:2014 standard, an impact ball is used for detecting the impact resistance of a sample object; according to the Shore hardness test method for plastics of GB 2411-1980(1989), the surface hardness of the sample object is detected by using a D-type hardness tester; the aging resistance of the sample object is detected by irradiating the sample object with UVA-340 fluorescent ultraviolet lamp and irradiating the sample object for 200 hours by a method A in the standard according to a sample method of the standard GB/T16422.3-2014 Plastic laboratory light source exposure test method part 3, namely fluorescent ultraviolet lamp and GB/T9341 Plastic bending property test method.

And (3) detection results: setting each sample object as five parallel groups for performance detection, wherein the average value of the wear quality of the five groups of sample objects is used as the evaluation of the wear resistance; recording the times of passing or failing after impact of the impact ball, and accumulating the times of failing as evaluation for judging the impact resistance; the mean value of the shore hardness of five groups of sample objects is used as the evaluation of the surface hardness; the average of the flexural strength of the five groups of sample objects after accelerated aging by ultraviolet irradiation was used as an evaluation of the aging resistance. The results of each test sample are detailed in table 2.

TABLE 2 Performance test results

Item	Quality of wear	Number of impact failures	Surface hardness	Bending strength
					Experimental sample 1	39.8mg	0	75D	17.6Mpa
Experimental sample 2	38.5mg	0	80D	18.4Mpa
					Experimental sample 3	38.0mg	0	77D	20.8Mpa
Experimental sample 4	38.2mg	0	78D	21.2Mpa
					Experimental sample 5	37.3mg	0	82D	22.7Mpa
Experimental sample 6	37.7mg	0	81D	23.0Mpa
					Control sample 1	41.0mg	4	74D	15.2Mpa
Control sample 2	47.6mg	4	68D	13.4Mpa
					Control sample 3	46.9mg	5	72D	12.0Mpa
Control sample 4	49.2mg	2	54D	15.9Mpa

According to the detection results in table 2, the wear mass of the experimental samples 1-6 is below 40mg, no impact failure occurs in the impact resistance test, and the surface hardness is above 75D, so that the foamed co-extruded layer formed by coating the foamed core layer with the surface co-extruded layer has mechanical properties similar to those of a non-porous plate, and has more excellent wear resistance and impact resistance compared with the conventional polyethylene foamed plate.

In addition, the experimental samples 1-6 have better wear resistance and impact resistance than the control sample 1, which shows that the addition of the melt reinforcing agent is beneficial to improving the overall mechanical property of the co-extruded foam board; compared with the control samples 2 to 4, the experimental samples 1 to 6 have higher wear resistance and impact resistance and higher surface hardness, which shows that the vinyl copolymer, the polyethylene elastomer and the surface filler can enable the quality of the co-extruded foam board to be more excellent. In addition, after the photoaging treatment, the bending strength of the experimental samples 1-6 is still kept at a higher level than that of the control samples 2-3, which shows that the addition of the vinyl copolymer and the polyethylene elastomer is beneficial to improving the bonding strength between the surface co-extruded layer and the foam core layer, so that the co-extruded foam board is not easy to have the phenomenon of surface layer separation, and has better durability.

The present embodiment is only for explaining the present application, and it is not limited to the present application, and those skilled in the art can make modifications of the present embodiment without inventive contribution as needed after reading the present specification, but all of them are protected by patent law within the scope of the claims of the present application.

Claims

1. The preparation method of the wood-grain-like HDPE co-extruded foam board is characterized by comprising the following preparation steps:

step 1) material preparation:

core layer mixture: uniformly mixing raw materials including 40-80 parts by weight of high-density polyethylene, 5.15-10.5 parts by weight of melt reinforcing agent, 10-40 parts by weight of core layer filler and 0.5-1.5 parts by weight of cross-linking agent to obtain a core layer mixture for later use;

surface layer mixture: mixing, plasticizing and granulating raw materials comprising 65-90 parts by weight of HDPE, 3-5 parts by weight of vinyl copolymer, 5-10 parts by weight of polyethylene elastomer, 3-10 parts by weight of surface layer filler and 1-5 parts by weight of compatilizer to prepare surface co-extrusion layer functional particles, dividing the surface co-extrusion layer functional particles into two parts, and respectively mixing 2-3 parts by weight of surface color master batches with different colors to obtain two parts of surface layer mixture for later use;

step 2) extruding a foaming core layer: pouring the prepared core layer mixture into a hopper of a core layer extruder (100) for melting and plasticizing, adding 0.4-5 parts of foaming agent and 0.4-2 parts of foaming activating agent into a homogenizing section at the rear end of a screw of the core layer extruder (100) for foaming, extruding into a core layer mold for foaming and molding, and then pre-shaping through a core layer cooling mold (101) to obtain a foamed core layer;

step 3) surface layer co-extrusion coating: the prepared two surface layer mixed materials are respectively put into hoppers of two surface layer extruders (200), the two surface layer extruders (200) respectively carry out melting plasticization on the poured surface layer mixed materials to obtain surface co-extrusion materials, the surface co-extrusion materials of one surface layer extruder (200) are converged into the other surface layer extruder (200) through a confluence core (201), meanwhile, a foaming core layer passes through the center of a co-extrusion die (300), the melted surface co-extrusion materials with two different colors are mixed and extruded to the co-extrusion die (300) and coated on the surface of a foaming core layer substrate to form a wood-like patterned surface co-extrusion layer;

step 4), cooling and shaping: after being extruded by the co-extrusion die, the HDPE co-extrusion foaming board with the wood grain is obtained through the shaping of the co-extrusion cooling die (301).

2. The method of claim 1, wherein the melt enhancer comprises: 0.15-0.5 part of coated polytetrafluoroethylene particles and 5-10 parts of ultrahigh molecular weight polyethylene.

3. The method for preparing the wood-like grain HDPE co-extruded foam board as claimed in claim 1, wherein the core layer mixture further comprises 1-2 parts by weight of a dispersant, wherein the dispersant is one or more of stearic acid, zinc stearate and calcium stearate.

4. The method of claim 1, wherein the foaming agent is one or more of sodium bicarbonate and azodicarbonamide, and the foaming activator is zinc oxide.

5. The method as claimed in claim 1, wherein the polyethylene-based elastomer is a combination of one or more of POE, TPO, and EVA.

6. The method of claim 1, wherein the vinyl copolymer is a combination of one or more of EAA, EEA, and EMAA.

7. The method of claim 1, wherein the surface filler is one or more of hollow glass beads, fumed silica, and talc.

8. The method for preparing the wood-like HDPE co-extruded foam board as claimed in any one of claims 1-7, wherein the plasticizing and granulating temperature is 160-200 ℃ when preparing the surface co-extruded layer functional particles; when the foaming core layer is prepared, the plasticizing temperature of the feeding section of the core layer extruder (100) is 140-160 ℃, and the foaming temperature of the homogenizing section is 180-200 ℃; when the surface co-extrusion layer is prepared, the working temperature of the surface layer extruder (200) is 190-210 ℃.

9. A wood grain-imitated HDPE co-extruded foam board, characterized in that the wood grain-imitated HDPE co-extruded foam board is prepared by the method for preparing the wood grain-imitated HDPE co-extruded foam board as claimed in any one of claims 1-8.

10. An HDPE surface co-extrusion layer functional particle, which is characterized in that the surface co-extrusion layer functional particle is the surface co-extrusion layer functional particle prepared by granulation in the step 1) in the preparation method of the wood-grain-like HDPE co-extrusion foaming board in any one of claims 1-8.