WO2017067504A1

WO2017067504A1 - Foamed pvc material, preparation method and use thereof

Info

Publication number: WO2017067504A1
Application number: PCT/CN2016/102868
Authority: WO
Inventors: 平田隆一; 束建强
Original assignee: 大电塑料（上海）有限公司
Priority date: 2015-10-21
Filing date: 2016-10-21
Publication date: 2017-04-27
Also published as: CN106609011B; CN106609011A

Abstract

The invention relates to the field of macromolecular materials, particularly to a foamed PVC material that is used as a sealant for a refrigerator door, and a preparation method and use thereof. The invention provides a foamed PVC material, the raw materials thereof comprising the following components calculated in parts by weight: 100 parts of a polyvinyl chloride; 60-90 parts of a plasticizer; 25-95 parts of a filling agent; 2.4-12 parts of a processing aid; 1.2-6 parts of a foaming agent; 0.2-0.5 parts of an antioxidant; 0.2-2.4 parts of a lubricant; and 1-8 parts of a stabilizer. The foamed PVC material provided by the invention obtains, when shaping a seal by means of an extruder, suitable foaming rate by means of controlling a dwell time and a processing temperature, efficiently saving social resources and reducing the cost, and reducing the coefficient of heat conductivity significantly. Meanwhile, the material prepared still has good mechanical performances.

Description

Foamed PVC material, preparation method and use thereof

Technical field

The invention relates to the field of polymer materials, in particular to a foamed PVC material which can be used for a door sealing material of a refrigerator, a preparation method thereof and a use thereof.

Background technique

The refrigerator door seal is a refrigerator accessory used for sealing between the door body of the refrigerator and the box body, which can ensure the fresh-keeping effect of the refrigerator, and can prolong the service life of the refrigerator, ensure that the door body of the refrigerator can be closed well, and reduce the interior of the refrigerator. Loss of energy. Under normal circumstances, the refrigerator door seal consists of two parts, one is a soft coat and the other is a magnetic strip.

The refrigerator door seals (ie, the soft outer jacket portions) used in the existing home appliance industry are generally produced from PVC materials through plastic extruders. PVC is an abbreviation for (Polyvinyl chloride) polyvinyl chloride resin. Polyvinyl chloride homopolymer and polyvinyl chloride copolymer are collectively referred to as polyvinyl chloride resin, which is homopolymerized by vinyl chloride monomer (VCM). Or a vinyl chloride monomer copolymerized with other monomers, the polyvinyl chloride resin is a white powder or microbeads, which are soft and hard depending on the composition. The PVC material is a material produced by adding a certain proportion of other materials to the polyvinyl chloride resin under certain temperature and pressure.

The refrigerator door seal materials used in the home appliance industry are all prepared from unfoamed PVC materials. The seal materials prepared have large thermal conductivity, poor heat insulation effect, high energy consumption, large usage, poor elastic modulus, and the like. problem.

Summary of the invention

In view of the above-mentioned shortcomings of the prior art, it is an object of the present invention to provide a foamed PVC material which can be used for a refrigerator door seal and a preparation method and use thereof for solving the problems in the prior art.

In order to achieve the above object and other related objects, a first aspect of the present invention provides a foamed PVC material comprising, by weight, parts by weight of the following components:

Preferably, the polyvinyl chloride has a degree of polymerization of from 800 to 2,500.

More preferably, the polyvinyl chloride has a degree of polymerization of from 1,000 to 1300.

Preferably, the plasticizer is selected from the group consisting of self-identifying diester polyester, trioctyl trimellitate (TOTM), epoxidized soybean oil (ESBO), dioctyl terephthalate (DOTP), and sebacic acid A combination of one or more of octyl (DOS), dioctyl adipate (DOA).

More preferably, the plasticizer is a combination of an adipic acid polyester and an epoxidized soybean oil, wherein the plasticizer has a weight ratio of adipic acid polyester to epoxidized soybean oil of 1:0.1- 1.5.

Further preferably, the preferred viscosity of the oxalic acid polyester is (25 ° C, Mpa·s) 2400-6000, specific gravity (20/20 ° C) 1.050-1.150, epoxy value of epoxy soybean oil (% ) 6.0 or more, the acid value (KOH mg / g) is 0.5 or less.

Preferably, the filler is calcium carbonate.

Preferably, the processing aid is selected from the group consisting of one or more of an acrylic processing aid and a methyl methacrylate processing aid.

More preferably, the processing aid is selected from the group consisting of acrylic processing aids.

Further preferably, the acrylic processing aid is a methyl methacrylate (MMA)/acrylate copolymer having a weight average molecular weight (×10 ⁴ ) of 250 or more.

Preferably, the blowing agent is a chemical blowing agent.

More preferably, the chemical blowing agent is selected from the group consisting of azodicarbonamide, sodium hydrogencarbonate, 4,4'-hydroxybisbenzenesulfonyl hydrazide, preferably a combination of organic chemical foaming Agent.

Preferably, the antioxidant is selected from the group consisting of one or more of antioxidant 1010, antioxidant 168, DLTP.

Preferably, the stabilizer is selected from the group consisting of calcium stearate, zinc stearate, β-diketone, hydrotalcite, rare earth stabilizer, organotin stabilizer, and antimony zinc stabilizer.

More preferably, the stabilizer comprises calcium stearate, zinc stearate, β-diketone and hydrotalcite, and the ratio by weight of each component is: calcium stearate, zinc stearate, β-di Ketone and hydrotalcite = 1-10:1-10:1-10:1-10.

Preferably, the raw material of the foamed PVC material further comprises 0.1-0.5 parts by weight of the anti-mold antibacterial agent.

Preferably, the raw material of the foamed PVC material further comprises, by weight, 3 to 15 parts of a modifier.

More preferably, the modifier is selected from the group consisting of one or more of MBS, nitrile rubber, and acrylate elastomer.

A second aspect of the invention provides a method for preparing the foamed PVC material, comprising the steps of:

1) mixing polyvinyl chloride, a filler, an antioxidant, a lubricant, and a stabilizer;

2) mixing an appropriate amount of plasticizer with the material obtained in step 1 at room temperature;

3) mixing the remaining plasticizer with the material obtained in step 2 at 70-90 ° C;

4) mixing the processing aid with the material obtained in step 3 at 125-135 ° C;

5) cooling the material obtained in step 4 to 90-110 ° C, adding a blowing agent and mixing;

6) The material obtained in the step 5 is subjected to internal hardening, and the material obtained by the kneading is extruded and granulated to obtain the foamed PVC material.

Preferably, the weight ratio of the plasticizer added in the step 2 and the step 3 is preferably 1:2-5.

Preferably, in the step 4, the processing aid and the modifier are mixed with the material obtained in the step 3.

Preferably, in the step 6, the specific conditions of the mixing are three-stage mixing, controlled by temperature and rotation speed, respectively, 80-90 ° C / 30-40 rpm, 100-110 ° C / 35-45 rpm, 110-120 °C/30-40rpm.

Preferably, in the step 6, the temperature at the time of extrusion granulation is 90-115 °C.

A third aspect of the invention provides the use of the foamed PVC material in the preparation of a PVC door seal.

Preferably, the foamed PVC material is used in the preparation of a PVC door seal for a refrigerator.

As described above, the foamed PVC material provided by the present invention obtains a suitable foaming rate by controlling the residence time and the processing temperature when being formed by the seal of the extruder, effectively saving social resources, reducing costs, and making the seals The thermal conductivity is significantly reduced, and at the same time, the material obtained by the preparation still has good mechanical properties.

detailed description

The inventor of the present invention adds a specific chemical foaming agent and the like to the PVC formulation, and uses a special processing method to ensure that the chemical foaming agent does not react when the PVC pellets are mixed and granulated, and only passes through the temperature when the door seal is extruded. The extrusion speed is used to ensure a certain foaming rate, so that a large amount of fine bubbles are introduced inside the PVC, and the material properties can be remarkably improved, and the mechanical properties of the PVC material are not lowered.

The invention provides a foamed PVC material, the raw material of which comprises the following components in parts by weight:

Preferably, the foamed PVC material provided by the present invention comprises the following components in parts by weight:

The components are described in detail below:

Polyvinyl chloride

In the formulation of the foamed PVC material provided by the present invention, polyvinyl chloride is used as a base in 100 parts by weight, and the remaining components are used in a certain weight ratio to the polyvinyl chloride. The polyvinyl chloride has a polymerization degree of 800-2500, a preferred degree of polymerization of 1000-1300, and a polyvinyl chloride having a degree of polymerization of 1000-1300 has the best processing property, mechanical properties, and cost performance.

Plasticizer

In the invention, the plasticizer is used for reducing the melting temperature and melt viscosity of the PVC material, and the product has good flexibility, elasticity and low temperature resistance.

In the foamed PVC material provided by the present invention, 60-90 parts of plasticizer is included in parts by weight, preferably 70-85 parts of plasticizer, and those skilled in the art can adjust plasticization according to different processes and environments. The amount of the agent. The plasticizer is preferably selected from the group consisting of self-identifying diester polyester, trioctyl trimellitate (TOTM), epoxidized soybean oil (ESBO), dioctyl terephthalate (DOTP), dioctyl sebacate. (DOS), a combination of one or more of dioctyl adipate (DOS), more preferably a combination of adipic acid polyester and epoxidized soybean oil, and the diacid polyester can impart superiority to the material. The ABS/PS resistance, the extraction resistance, the excellent resilience, etc., the epoxy soybean oil can impart the necessary extraction resistance and thermal stability of the material, and the two can be combined to achieve the best use effect. The weight ratio of both the adipic acid polyester and the epoxidized soybean oil in the plasticizer is preferably adipic acid polyester: epoxidized soybean oil = 1: 0.1 to 1.5, more preferably 1: 0.3 to 1.2. The adipic acid-based polyester is specifically a polymer formed by polycondensation of adipic acid with a diamine or a glycol, and the adipic acid-based polyester includes, but is not limited to, polyethylene adipate. , polyadipate-1,2-propanediol ester, polyadipate-1,3-butylene glycol ester, polyadipate-1,4-butanediol ester, polyadipylate adipate, a combination of one or more of polyadipate-1,6-hexanediol ester, polyhexamethylene adipate, etc., the preferred viscosity of the adipic acid-based polyester is (25 ° C, Mpa· s) 2400-6000, preferably having a specific gravity of (20/20 ° C) 1.050-1.150 (the ratio of the density of the substance (fully compacted state) to the density of pure H ₂ O at 20 ° C under standard atmospheric pressure), in the present invention In one embodiment, the adipic acid type polyester is W-2310, and the supplier is a large Japanese ink company; preferably, the epoxy soybean oil has an epoxy value (%) of 6.0 or more, and an acid value (KOH) Mg/g) 0.5 or less, in an embodiment of the invention, the epoxidized soybean oil is model E-20, and the supplier is Guangzhou Xinjinlong Plastic Additive Co., Ltd.

Filler

In the foamed PVC material provided by the present invention, 25 to 95 parts by weight, preferably 40 to 80 parts, of filler are included in parts by weight. A preferred filler is calcium carbonate, and the calcium carbonate may be a light calcium carbonate or a heavy calcium carbonate as long as it does not limit the object of the present invention. The heavy calcium carbonate refers to a sedimentation volume ratio of 1.1-1.9 mL / g of calcium carbonate, light calcium carbonate sedimentation volume ratio of 2.4-2.8 mL / g of calcium carbonate. In a preferred embodiment of the invention, the model of heavy calcium carbonate is LD-800 and the supplier is Rieter Supermicro Industrial (Suzhou) Co., Ltd.

Processing aids

Because the distribution and size of the pores of PVC materials are obviously uneven, the stress is concentrated on the thin surface during the tensile test, which is easy to break. Therefore, it is necessary to select appropriate processing aids and addition amount to ensure the distribution and size of the pores. Uniform, thereby increasing tensile strength.

In the foamed PVC material provided by the present invention, 2.4 to 12 parts by weight of a processing aid, preferably 2.4 to 5.5 parts, of a processing aid are included. The processing aid is selected from the group consisting of one or more of an acrylic processing aid and a methyl methacrylate processing aid, preferably an acrylic processing aid. Further, the acrylic processing aid is preferably a methyl methacrylate (MMA) / acrylate copolymer. Preferably, the weight average molecular weight (×10 ⁴ ) of the methyl methacrylate (MMA)/acrylate copolymer is 250 or more; in an embodiment of the invention, the type of the acrylic processing aid is P- 531A, the supplier is Mitsubishi Rayon (Shanghai) Management Co., Ltd.

Foaming agent

In the foamed PVC material provided by the present invention, 1.2 to 6 parts by weight of the foaming agent is contained, preferably 1.5 to 3 parts by weight of the foaming agent. The foaming agent is preferably a chemical foaming agent, and specific chemical foaming agents may be used, including but not limited to: one of azodicarbonamide, sodium hydrogencarbonate, and 4,4'-hydroxybisbenzenesulfonylhydrazide. Or a combination of multiples. More preferably, it is an organic chemical foaming agent. In a preferred embodiment of the present invention, the organic chemical foaming agent is azodicarbonamide, and is combined with a suitable stabilizer to reduce azodicarbonamide well. The decomposition temperature allows it to be used as a blowing agent in PVC material systems.

Antioxidant

In the foamed PVC material provided by the present invention, the antioxidant is used to retard or inhibit the progress of oxidation of the polymer, thereby preventing aging of the polymer and prolonging its service life.

In the foamed PVC material provided by the present invention, 0.2 to 0.5 parts by weight of the antioxidant, preferably 0.2 to 0.3 parts by weight of the antioxidant are included in parts by weight. The antioxidant may use various antioxidants in the art, and specifically, antioxidants including, but not limited to, antioxidant 1010 (tetrakis [β-(3,5-di-tert-butyl-4-hydroxybenzene) One or more of propionic acid] pentaerythritol ester), antioxidant 168 (phenyl (tris(2,4-di-tert-butyl) phosphite), DLTP (dual lauryl thiodipropionate) combination. In a preferred embodiment of the invention, the antioxidant is an antioxidant 1010.

Lubricant

The function of the lubricant in the present invention is to improve the fluidity of the product during processing, to prevent defects due to adhesion in the machine, and to improve the processability of the material.

In the foamed PVC material provided by the present invention, 0.2 to 2.4 parts by weight of the lubricant is included by weight, and those skilled in the art can adjust the amount of the lubricant according to the kind of the lubricant, the process, and the use environment. The lubricant may use various lubricants in the art, and specifically, lubricants that may be used include, but are not limited to, one or a combination of stearic acid and oxidized polyethylene. In a preferred embodiment of the invention, the lubricant is stearic acid.

stabilizer

In the foamed PVC material provided by the invention, the stabilizer acts to delay the thermal decomposition thereof, and at the same time cooperates with the foaming agent to reduce the decomposition temperature of the foaming agent.

In the foamed PVC material provided by the present invention, 1-8 parts by weight, preferably 1-6 parts of stabilizer, are included in parts by weight, and those skilled in the art can adjust the plasticizer according to the process and the use environment. Dosage. The stabilizer includes a PVC heat stabilizer and an acid acceptor, and preferred PVC heat stabilizers include, but are not limited to, calcium stearate, zinc stearate, β-diketone (stearoylbenzoylmethane), diphenyl. A combination of one or more of formylmethane, preferred acid acceptors include, but are not limited to, hydrotalcite, which is preferably Mg ₄ Al ₂ (OH) ₁₂ CO ₃ .3H ₂ O. In a preferred embodiment of the present invention, the stabilizer comprises calcium stearate, zinc stearate, β-diketone and hydrotalcite, and the ratio by weight of each component is: calcium stearate, stearic acid Zinc, β-diketone and hydrotalcite = 0.10-1: 0.1-10: 0.1-10: 0.1-10, preferably calcium stearate, zinc stearate, β-diketone and hydrotalcite = 0.4-0.8: 0.4-0.8: 0.1-0.5: 0.5-4, the hydrotalcite is of the type HT-1, and the supplier is Nippon Chemical Co., Ltd.

Anti-mold antibacterial agent

In the foamed PVC material provided by the present invention, 0.1 to 0.5 parts of an antifungal antibacterial agent may also be included. The kind of the anti-mold antibacterial agent is not particularly limited as long as it does not limit the object of the present invention. Specific anti-fungal antibacterial agents that can be used include, but are not limited to, thiabendazole.

Modifier

In the foamed PVC material provided by the present invention, 3 to 15 parts by weight of the modifier may be further included, and preferably 5 to 15 parts of the modifier may be included. The modifier may be a combination of one or more of, including but not limited to, MBS, nitrile rubber, acrylate elastomer, and the like. The MBS is a terpolymer of methyl methacrylate (M), butadiene (B) and styrene (S), and the ratio of the monomers in the MBS may be B: S=50-70:30 -50, more specifically M: B: S = 20-40: 35-55: 20-40; the nitrile rubber (butyronitrile elastomer) is pre-crosslinked by copolymerization of butadiene and acrylonitrile The structural elastomer (rubber), the content of the acrylonitrile monomer in the nitrile rubber may be 23-43%, more specifically 28-38%, the Mooney viscosity ML1+4, 100 ° C may be 37-77, Specifically, it may be 47-67. In an embodiment of the invention, the nitrile rubber is P-83, and the supplier is French Onofrio Chemical. The acrylate elastomer (acrylate rubber) is An elastomer having a pre-crosslinked structure obtained by copolymerization of an acrylate-based monomer, the acrylate elastomer having a Mooney viscosity ML1+4, 150 ° C may be 15-35, more specifically 20-30, in the present invention In one embodiment, the acrylate elastomer is P-95 and the supplier is French Onofrio Chemical.

The invention further provides a preparation method of the foamed PVC material, which performs necessary control on the processing temperature during the preparation process, and the foaming agent does not decompose, specifically comprising the following steps:

In order to allow the resin powder to absorb the plasticizer well, a small amount of plasticizer is added to allow the resin powder to be absorbed at room temperature (preferably 5-35 ° C), and the remaining plasticization is carried out when the temperature is raised to about 80 ° C. All the agents are added to the mixing pot to allow the resin powder to have sufficient time to absorb and mix.

A person skilled in the art can adjust the weight ratio of the plasticizers added in steps 2 and 3 according to the actual application. Preferably, the weight ratio of the plasticizer added in the steps 2 and 3 is preferably 1. : 2-5.

When the modifier is further included in the foamed PVC material, in the step 4, the processing aid and the modifier may be mixed with the material obtained in the step 3.

During the entire material mixing process, the temperature of the material system does not exceed 140 °C.

In the steps 4 and 5, the processing aid is mixed with the material obtained in the step 3. Because of the high-speed mixing of the mixing pot, the material will heat up during the mixing process, and the cooling system (cooling) is adopted when the temperature is raised to 130-140 ° C. Water) The material was cooled to 90-110 ° C, the blowing agent was added and mixed for 3 minutes, and the temperature of the system was maintained at 90-110 ° C during the mixing.

In an embodiment of the present invention, the specific conditions of the mixing are three-stage mixing, controlled by temperature and rotation speed, and the three-stage mixing temperature is 80-90 ° C / 30-40 rpm, 100-110 ° C / 35- 45 rpm, 110-120 ° C / 30-40 rpm, the temperature at the time of extrusion granulation is ≤ 115 ° C, and the preferred temperature is 90-115 ° C.

In an embodiment of the present invention, the mixing of the materials is carried out in a high-speed mixing pan. In each step, the specific conditions for mixing are as follows:

2) mixing an appropriate amount of plasticizer with the material obtained in step 1 at 5-35 ° C;

4) The weight ratio of the plasticizer added in the step 2 and the step 3 is preferably 1:2-5.

5) The processing aid is mixed with the material obtained in the step 3 at 125-135 ° C. When the temperature of the system is raised to 130-140 ° C, the material is cooled to 90-110 ° C, the blowing agent is added and mixed for 3 minutes.

The invention further provides the use of the foamed PVC material in the preparation of a PVC door seal.

Preferably, the foamed PVC material is used in the preparation of a PVC door seal for a refrigerator. The foamed PVC material provided by the invention is particularly suitable for preparing PVC door sealing material for refrigerators, and the door sealing material introduces a large amount of micro-bubbles inside the PVC by adding a foaming agent, thereby significantly improving the heat insulating performance of the material while ensuring The mechanical properties of the material are suitable for the complex structure and use environment of the refrigerator door seal.

The invention further provides a foamed PVC door seal material obtained by preparing the foamed PVC material.

In the foamed PVC material, azodicarbonamide is not decomposed, and during the preparation process of preparing the foamed PVC door sealant using the foamed PVC material, azodicarbonamide is decomposed and foamed.

In the present invention, the foamed PVC door seal can be obtained from the foamed PVC material by various extruders in the art. During processing, the processing temperature is preferably from 115 to 170 ° C. In one embodiment of the invention, the processing temperature is from 140 to 158 ° C. In one embodiment of the invention, the processing temperature is from 150 to 168 ° C. Those skilled in the art can adjust the residence time according to different equipment, process and use environment (specifically, different diameters of the extruder, different processing temperatures, etc.) to obtain a suitable foaming rate. The preferred foaming ratio of the sealant is 13-40%.

The embodiments of the present invention are described below by way of specific examples, and those skilled in the art can readily understand other advantages and effects of the present invention from the disclosure of the present disclosure. The present invention may be embodied or applied in various other specific embodiments, and various modifications and changes can be made without departing from the spirit and scope of the invention.

It should be noted that the process equipment or apparatus not specifically noted in the following examples employ conventional equipment or apparatus in the art.

In addition, it should be understood that one or more of the method steps recited in the present invention are not exclusive of other method steps that may be present before or after the combination step, or that other method steps can be inserted between the steps specifically mentioned, unless otherwise It should be understood that the combined connection relationship between one or more devices/devices referred to in the present invention does not exclude that other devices/devices may exist before or after the combined device/device or Other devices/devices can also be inserted between the two devices/devices unless otherwise stated. Moreover, unless otherwise indicated, the numbering of each method step is merely a convenient means of identifying the various method steps, and is not intended to limit the order of the various method steps or to limit the scope of the invention, the relative In the case where the technical content is not substantially changed, it is considered to be a scope in which the present invention can be implemented.

The product information used in the specific examples is as follows:

Example 1

The preparation method of the foamed PVC door sealing material is as follows:

1) According to the formula in Table 1, the polyvinyl chloride, the filler, the antioxidant, the lubricant and the stabilizer are added to the high-speed mixing pot for mixing;

2) After mixing at a high speed for 60±20 seconds, an appropriate amount of plasticizer is mixed with the material obtained in step 1, and the mixing temperature is room temperature;

3) mixing the remaining plasticizer with the material obtained in step 2 at 80 ° C;

The weight ratio of the plasticizer added in the step 2 and the step 3 is preferably 1:4.

4) mixing the processing aid with the material obtained in step 3 at 130 ° C;

5) Stop at 135 ° C;

6) Cooling water is cooled, the material is cooled to 90-110 ° C, foaming agent is added and mixed for 3 minutes; (unexpanded product does not have this step)

7) The obtained materials are mixed, and the specific conditions of the mixing are three-stage mixing and controlled by temperature, which are 85 ° C / 35 rpm, 105 ° C / 40 rpm, 115 ° C / 35 rpm, and the materials obtained by the mixing are at 90. Extrusion granulation at -115 ° C;

The pellet obtained in the step 7 is passed through a φ20 mm extrusion test machine to prepare a spline of the foamed PVC door sealing material, and the processing temperature is 140 ° C - 158 ° C;

Extruder speed: 30 rpm, residence time: 2 min.

Table 1

The splines obtained in the above preparation were tested for performance. The specific results are shown in Table 2:

The tensile strength is in accordance with JIS K 6723 6.3, and the tensile speed is 200 mm/min;

The elongation at break is carried out in accordance with JIS K 6723 6.3, and the drawing speed is 200 mm/min;

The specific gravity is in accordance with JIS K 7112A;

The thermal conductivity is calculated according to the formula using thermal diffusivity, constant pressure specific heat capacity, and specific gravity.

Table 2

Related formula: thermal conductivity = thermal diffusivity * constant pressure specific heat capacity * specific gravity

Foaming rate = specific gravity of unfoamed product / specific gravity of foamed product -1

Example 2

The preparation method of the foamed PVC door sealing material is as follows:

1) According to the formula in Table 3, the polyvinyl chloride, the filler, the antioxidant, the lubricant and the stabilizer are added to the high-speed mixing pot for mixing;

2) mixing a suitable amount of plasticizer with the material obtained in step 1 after mixing at a high speed of ° C for 60 seconds ± 20;

4) mixing the processing aid with the material obtained in step 3 at 130 ° C;

5) Stop at 135 ° C;

The pellet obtained in the step 7 is passed through a φ20 mm extrusion test machine to prepare a spline of the foamed PVC door sealing material, and the processing temperature is 140-158 ° C;

Extruder speed: 30 rpm, residence time: 2 min.

table 3

The splines obtained in the above preparation were tested for performance. The specific results are shown in Table 4:

The specific gravity is in accordance with JIS K 7112A;

Table 4

Example 3

The preparation method of the foamed PVC door sealing material is as follows:

1) according to the formula in Table 5, the polyvinyl chloride, filler, antioxidant, lubricant, stabilizer is added to the high-speed mixing pot for mixing;

3) mixing the remaining plasticizer with the material obtained in step 2 at 70 ° C;

The weight ratio of the plasticizer added in the step 2 and the step 3 is preferably 1:2.

4) mixing the processing aid with the material obtained in step 3 at 125 ° C;

5) Stop at 135 ° C;

7) The obtained materials are mixed, and the specific conditions of the mixing are three-stage mixing and controlled by temperature, which are 80 ° C / 30 rpm, 110 ° C / 45 rpm, 120 ° C / 40 rpm, and the materials obtained by the mixing are 90. Extrusion granulation at -115 ° C;

Extruder speed: 30 rpm, residence time: 2 min.

table 5

The splines obtained in the above preparation were tested for performance. The specific results are shown in Table 6:

The specific gravity is in accordance with JIS K 7112A;

Table 6

Example 4

The preparation method of the foamed PVC door sealing material is as follows:

1) According to the formula in Table 7, the polyvinyl chloride, the filler, the antioxidant, the lubricant and the stabilizer are added to the high-speed mixing pot for mixing;

3) mixing the remaining plasticizer with the material obtained in step 2 at 90 ° C;

The weight ratio of the plasticizer added in the step 2 and the step 3 is preferably 1:5.

4) mixing the processing aid with the material obtained in step 3 at 135 ° C;

5) Stop at 140 °C;

7) The obtained materials are mixed, and the specific conditions of the mixing are three-stage mixing, controlled by temperature, respectively, at 90 ° C / 40 rpm, 100 ° C / 35 rpm, 110 ° C / 30 rpm, and the materials obtained by the mixing are at 90 Extrusion granulation at -115 ° C;

Extruder speed: 30 rpm, residence time: 2 min.

Table 7

The splines obtained in the above preparation were tested for performance. The specific results are shown in Table 8:

The specific gravity is in accordance with JIS K 7112A;

Table 8

Example 5

The preparation method of the refrigerator door seal is as follows:

1) According to the formula in Table 9, the polyvinyl chloride, the filler, the antioxidant, the lubricant and the stabilizer are added to the high-speed mixing pot for mixing;

4) mixing the processing aid and the modifier with the material obtained in step 3 at 130 ° C;

5) Stop at 135 ° C;

The pellet obtained in step 7 is passed through a φ20 mm extrusion test machine to prepare a spline of the refrigerator door seal, and the processing temperature is 140-158 ° C;

Extruder speed: 30 rpm, residence time: 2 min.

Table 9

The splines obtained in the above preparation were tested for performance. The specific results are shown in Table 10:

The specific gravity is in accordance with JIS K 7112A;

Table 10

Example 6

The preparation method of the refrigerator door seal is as follows:

1) According to the formula in Table 11, the polyvinyl chloride, the filler, the antioxidant, the lubricant and the stabilizer are added to the high-speed mixing pot for mixing;

5) Stop at 135 ° C;

Extruder speed: 30 rpm, residence time: 2 min.

Table 11

The splines obtained in the above preparation were tested for performance. The specific results are shown in Table 12:

The specific gravity is in accordance with JIS K 7112A;

Table 12

Example 7

The preparation method of the refrigerator door seal is as follows:

1) According to the formula in Table 13, the polyvinyl chloride, the filler, the antioxidant, the lubricant and the stabilizer are added to the high-speed mixing pot for mixing;

5) Stop at 135 ° C;

The pellet obtained in step 7 is passed through a φ20 mm extrusion test machine to prepare a spline of the refrigerator door seal, and the processing temperature is 150-168 ° C;

Extruder speed: 30 rpm, residence time: 2 min.

Table 13

The splines obtained in the above preparation were tested for performance. The specific results are shown in Table 14:

The specific gravity is in accordance with JIS K 7112A;

Table 14

In summary, the present invention effectively overcomes various shortcomings in the prior art and has high industrial utilization value.

The above-described embodiments are merely illustrative of the principles of the invention and its effects, and are not intended to limit the invention. Modifications or variations of the above-described embodiments may be made by those skilled in the art without departing from the spirit and scope of the invention. Therefore, all equivalent modifications or changes made by those skilled in the art without departing from the spirit and scope of the invention will be covered by the appended claims.

Claims

A foamed PVC material, the raw materials of which include the following components by weight:
A foamed PVC material according to claim 1, wherein said polyvinyl chloride has a degree of polymerization of from 800 to 2,500, preferably from 1,000 to 1,300.
A foamed PVC material according to claim 1, wherein said plasticizer is selected from the group consisting of self-acidic polyester, trioctyl trimellitate, epoxidized soybean oil, and dioctyl terephthalate. A combination of one or more of an ester, dioctyl sebacate, and dioctyl adipate.
A foamed PVC material according to claim 3, wherein said plasticizer is a combination of adipic acid polyester and epoxidized soybean oil, wherein said plasticizer is adipic acid. The weight ratio of ester to epoxidized soybean oil is from 1:0.1 to 1.5.
A foamed PVC material according to claim 3, wherein the viscosity of the oxalic acid polyester is (25 ° C, Mpa·s) 2400-6000, and the specific gravity is (20/20 ° C) 1.050. -1.150, the epoxy value (%) of the epoxidized soybean oil is 6.0 or more, and the acid value (KOH mg/g) is 0.5 or less.
A foamed PVC material according to claim 1 wherein said filler is calcium carbonate.
A foamed PVC material according to claim 1 wherein said processing aid is selected from the group consisting of one or more of an acrylic processing aid and a methyl methacrylate processing aid.
A foamed PVC material according to claim 7, wherein said acrylic processing aid is a methyl methacrylate (MMA) / acrylate copolymer having a weight average molecular weight (×10 4 ) of 250 the above.
A foamed PVC material according to claim 1 wherein said chemical blowing agent is an organic chemical blowing agent.
A foamed PVC material according to claim 9, wherein said chemical foaming agent is selected from the group consisting of azodicarbonamide, sodium hydrogencarbonate, and 4,4'-hydroxybisbenzenesulfonylhydrazide. Combination of species or multiples.
A foamed PVC material according to claim 1 wherein said antioxidant is selected from the group consisting of one or more of antioxidant 1010, antioxidant 168, DLTP.
A foamed PVC material according to claim 1, wherein said stabilizer is selected from the group consisting of calcium stearate, zinc stearate, beta-diketone, hydrotalcite, rare earth stabilizer, and organotin stabilizer. a combination of one or more of zinc antimony stabilizers.
A foamed PVC material according to claim 12, wherein said stabilizer comprises calcium stearate, zinc stearate, ?-diketone and hydrotalcite, and the ratio by weight of each component is : calcium stearate, zinc stearate, β-diketone and hydrotalcite = 1-10:1-10:1-10:1-10.
A foamed PVC material according to claim 1, wherein the raw material of the foamed PVC material further comprises, for example, 0.1 to 0.5 parts by weight of the antibacterial agent.
A foamed PVC material according to claim 1, wherein the raw material of the foamed PVC material further comprises, by weight, 3 to 15 parts of a modifier.
A foamed PVC material according to claim 15 wherein said modifier is selected from the group consisting of one or more of MBS, nitrile rubber, and acrylate elastomer.
The method for preparing a foamed PVC material according to any one of claims 1 to 16, comprising the steps of:

1) mixing polyvinyl chloride, a filler, an antioxidant, a lubricant, and a stabilizer;

2) mixing an appropriate amount of plasticizer with the material obtained in step 1 at room temperature;

3) mixing the remaining plasticizer with the material obtained in step 2 at 70-90 ° C;

4) mixing the processing aid with the material obtained in step 3 at 125-135 ° C;

5) cooling the material obtained in step 4 to 90-110 ° C, adding a blowing agent and mixing;

6) The material obtained in the step 5 is subjected to internal hardening, and the material obtained by the kneading is extruded and granulated to obtain the foamed PVC material.
The preparation method according to claim 17, wherein the weight ratio of the plasticizer added in the step 2 and the step 3 is preferably 1:2 to 5.
The preparation method according to claim 17, wherein in the step 4, the processing aid and the modifier are mixed with the material obtained in the step 3.
The preparation method according to claim 17, wherein in the step 6, the specific conditions of the mixing are three-stage mixing, and the temperature and the rotation speed are controlled, respectively, 80-90 ° C / 30-40 rpm, 100. -110 ° C / 35-45 rpm, 110-120 ° C / 30-40 rpm.
The production method according to claim 17, wherein in the step 6, the temperature at the time of extrusion granulation is from 90 to 115 °C.
Use of a foamed PVC material according to any of claims 1-16 in the preparation of a PVC door seal.
The use according to claim 22, wherein the PVC door seal is a PVC door seal for a refrigerator.