阅读说明：本技术 发泡改性剂、发泡母粒、发泡材料及其制备方法 (Foaming modifier, foaming master batch, foaming material and preparation method thereof ) 是由 洪剑城 卢健体 罗贤祖 于 2020-07-31 设计创作，主要内容包括：本发明提供了一种发泡改性剂、发泡母粒、发泡材料及其制备方法。其中发泡改性剂以硝酸铁为吸热剂、硝酸铜或硫酸铜为缓释剂,配合包覆材料,配制出发泡改性剂。将发泡改性剂,发泡剂、载体及助剂混合挤出即制得发泡母粒。制得的发泡母粒具有起始分解温度高,分解速度慢,分解温度范围宽的特点。同时,发泡改性剂中的吸热剂分解亦可产生气体,从而提高了发泡倍率。基于发泡母粒的上述特性,可在具有高流动性的树脂基体中制备出发泡效率高,泡孔孔径小,外观无气痕、料花、起皮分层等表观缺陷,力学性能高的发泡材料。(The invention provides a foaming modifier, a foaming master batch, a foaming material and a preparation method thereof. Wherein the foaming modifier is prepared by taking ferric nitrate as a heat absorbing agent and copper nitrate or copper sulfate as a slow release agent and matching with a coating material. And mixing and extruding the foaming modifier, the foaming agent, the carrier and the auxiliary agent to obtain the foaming master batch. The prepared foaming master batch has the characteristics of high initial decomposition temperature, low decomposition speed and wide decomposition temperature range. Meanwhile, the decomposition of the heat absorbent in the foaming modifier can also generate gas, thereby improving the foaming ratio. Based on the characteristics of the foaming master batch, the foaming material with high foaming efficiency, small pore diameter, no surface defects of air mark, material flower, peeling, layering and the like and high mechanical property can be prepared in a resin matrix with high fluidity.)

1. The foaming modifier is characterized by comprising the following components in parts by weight: 1-5 parts of a slow release agent; 1-5 parts of a heat absorbent; 5-15 parts of a coating material;

the slow release agent is copper sulfate; the heat absorbing agent is ferric nitrate; the cladding material comprises a first layer of cladding material and a second layer of cladding material;

the first layer of coating material consists of erucamide, stearic acid and zinc stearate;

the second layer of coating material consists of hydroxy polydimethylsiloxane, hydrogen-containing silicone oil and a platinum catalyst.

2. The foaming modifier of claim 1, wherein the mass ratio of erucamide, stearic acid and zinc stearate in the first layer of coating material is (1-3): 0.5-1.5): 1; and/or

In the second layer coating material, the mass ratio of the hydroxyl polydimethylsiloxane, the hydrogen-containing silicone oil and the platinum catalyst is 1 (0.5-1.5) to 0.004-0.006.

3. The foam modifier of claim 1 or 2, wherein the hydroxy polydimethylsiloxane has a viscosity of less than 0.08 Pa/s.

4. The foaming master batch is characterized by comprising the following raw materials in percentage by weight:

5. the foaming concentrate of claim 4, wherein the polyethylene is selected from one of high density polyethylene, low density polyethylene, and linear low density polyethylene; and/or

The vinyl elastomer is selected from one of ethylene-butylene copolymer, ethylene-octene copolymer and ethylene propylene diene monomer; and/or

The foaming agent is sodium bicarbonate; and/or

The processing aid consists of an antioxidant, a light stabilizer and a metal passivator.

6. The blowing agent of claim 5, wherein the polyethylene is a low density polyethylene having an Mw/Mn of > 5 and a melt index of > 40g/10min at 190 ℃ under a 2.16kg load; and/or

The vinyl elastomer is an ethylene-octene copolymer, and the melt index of the vinyl elastomer is more than or equal to 30g/10min at 230 ℃ under a load of 2.16 kg; and/or

The antioxidant is selected from one or two of hindered phenol antioxidant tetra [ beta- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionic acid ] pentaerythritol ester and phosphite antioxidant tris (2, 4-di-tert-butyl) phenyl phosphite; and/or

The light stabilizer is hindered amine light stabilizer bis-2, 2,6, 6-tetramethyl piperidinol sebacate; and/or

The metal passivator is N, N' -bis [ beta- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionyl ] hydrazine.

7. The method for preparing the foaming concentrate of any one of claims 4-6, comprising the steps of:

1) mixing and stirring a foaming agent and a heat absorbing agent, adding a first layer of coating material, heating, adding a slow release agent, stirring, then adding hydroxyl polydimethylsiloxane and hydrogen-containing silicone oil, and stirring to obtain a mixture A;

2) putting polyethylene, vinyl elastomer, platinum catalyst, the mixture A prepared in the step 1) and processing aid into a mixer in proportion, mixing and stirring, melting and extruding in a double-screw extruder, and granulating to obtain the polyethylene-vinyl elastomer-platinum catalyst.

8. The method for preparing the foaming concentrate as claimed in claim 7, wherein the heating temperature in step 1) is 70-90 ℃; and/or

The temperature of the melt extrusion is 90-110 ℃, the length-diameter ratio of a screw of the double-screw extruder is 36-40:1, and the rotating speed of the double-screw extruder is 400-450 r/min.

9. A microcellular foamed material prepared from the foaming concentrate of any one of claims 4 to 6 and a microcellular foamed matrix resin; the mass ratio of the foaming master batch to the micro-foaming matrix resin is 1-2: 100;

the micro-foaming matrix resin comprises the following components in percentage by weight:

64.4 percent of polypropylene, 15 percent of ethylene-octene copolymer, 20 percent of talcum powder and 0.6 percent of processing agent;

the processing aid is preferably composed of antioxidant tetra [ beta- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionic acid ] pentaerythritol ester, phosphite antioxidant tri (2, 4-di-tert-butyl) phenyl phosphite and light stabilizer bis-2, 2,6, 6-tetramethylpiperidinol sebacate according to the proportion of 1:1: 1.

10. A preparation method of a micro-foaming material is characterized in that the foaming master batch and the micro-foaming matrix resin according to any one of claims 4 to 6 are added into an injection molding machine for injection molding according to the mass ratio of 1-2:100, and the conditions are as follows: the injection speed is 80-100mm/s, the injection pressure is 80-100bar, the injection time is 0.8-1.2s, the pressure is not maintained, and the cooling time is 7-9 s.

Technical Field

The invention belongs to the field of materials, and particularly relates to a foaming modifier, a foaming master batch, a foaming material and a preparation method thereof.

Background

Under the promotion of the trend of light weight of automobiles, the micro-foaming material is used as an air-filled composite material, has the characteristics of low density and obvious weight reduction effect, and has a compact surface layer and foam core layer structure, so that the micro-foaming material has slight influence on the performance of a workpiece and is highly advocated. However, the appearance problems of gas marks, material flowers, peeling and layering, and the like, which are commonly existed in the appearance of the micro-foamed polypropylene prepared by the chemical foaming mode, affect the beauty of the finished product in the injection molding process. The internal structure of the part has the problems of overlarge pore diameter of the pores, poor uniformity of the pore diameter, hole mixing and the like, so that the performance of the part is influenced. These are related to the structure of the mould, the way of shaping, the auxiliary techniques and the melt strength of the foaming base material, and are also closely related to the decomposition characteristics of the foaming agent.

The patent document with publication number CN108546405A discloses a micro-foamed injection molding nylon material with high surface quality, which forms a physical and chemical micro-cross-linking structure by adjusting the formula, improves the melt strength of the nylon material, and obtains a micro-foamed injection molding nylon material with fine, uniform and compact cells, and good mechanical properties and high surface appearance. Patent document CN105566751A discloses a high-crystallinity polypropylene foaming masterbatch and a preparation method thereof, wherein the foaming masterbatch reduces the mechanical property reduction caused by chemical foaming by improving the mechanical property of a non-foaming area in the injection foaming process.

When the decomposition rate of the foaming agent is uniform, the higher the melt strength of the foaming base material is, the more excellent the foam locking ability is, and the better the appearance of the product is. However, the higher the melt strength of the base material is, the lower the relative fluidity tends to be, especially for polypropylene materials, the fluidity of high melt strength polypropylene materials prepared by crosslinking and grafting is obviously reduced, the resistance to gas foaming expansion is increased, and the foaming ratio tends not to be high. For a material with high flow and high melt strength, due to the limited shear dispersion capacity of a molten gel storage of injection molding equipment, when the decomposition speed of the foaming agent is too high, part of the foaming agent is decomposed and expanded into local large cells, although the melt strength is high, the cells are not broken, the good appearance of a finished piece is ensured, the local large cells can cause stress concentration, and even if the mechanical property of a non-foaming area is very high, the stress concentration can also seriously affect the performance of the finished piece.

Disclosure of Invention

Based on the above, the invention aims to provide a foaming modifier, a foaming master batch, a foaming material and a preparation method thereof, wherein the prepared foaming master batch has the characteristics of high foaming proportion and small pore diameter of pores, eliminates the appearance defects of gas marks, material flowers, peeling and layering and the like in the process of micro-foaming material, and has good mechanical properties and appearance effects.

The specific technical scheme is as follows:

a foaming modifier comprises the following components in parts by weight: 1-5 parts of a slow release agent; 1-5 parts of a heat absorbent; 5-15 parts of a coating material;

the slow release agent is copper sulfate; the heat absorbing agent is ferric nitrate; the cladding material comprises a first layer of cladding material and a second layer of cladding material;

the first layer of coating material consists of erucamide, stearic acid and zinc stearate;

the second layer of coating material consists of hydroxy polydimethylsiloxane, hydrogen-containing silicone oil and a platinum catalyst.

The invention also provides a foaming master batch, which has the following specific technical scheme:

the foaming master batch comprises the following raw materials in percentage by weight:

the invention also provides a preparation method of the foaming master batch, and the specific technical scheme is as follows.

A preparation method of foaming master batches comprises the following steps:

1) mixing and stirring a foaming agent and a heat absorbing agent, adding a first layer of coating material, heating, adding a slow release agent, stirring, then adding hydroxyl polydimethylsiloxane and hydrogen-containing silicone oil, and stirring to obtain a mixture A;

2) putting polyethylene, vinyl elastomer, platinum catalyst, the mixture A prepared in the step 1) and processing aid into a mixer in proportion, mixing and stirring, melting and extruding in a double-screw extruder, and granulating to obtain the polyethylene-vinyl elastomer-platinum catalyst.

The invention also provides a specific technical scheme of the micro-foaming material.

A micro-foaming material is prepared from the foaming master batch and the micro-foaming matrix resin; the mass ratio of the foaming master batch to the micro-foaming matrix resin is 1-2: 100;

the micro-foaming matrix resin comprises the following components in percentage by weight:

64.4 percent of polypropylene, 15 percent of ethylene-octene copolymer, 20 percent of talcum powder and 0.6 percent of processing aid.

Preferably, the melt index of the polypropylene is more than or equal to 80g/10min at 230 ℃ under the load of 2.16 kg; and/or

The ethylene-octene copolymer has a melt index of more than or equal to 2g/10min at 190 ℃ under a load of 2.16 kg; and/or

The processing aid is composed of antioxidant tetra [ beta- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionic acid ] pentaerythritol ester, phosphite antioxidant tri (2, 4-di-tert-butyl) phenyl phosphite and light stabilizer bis-2, 2,6, 6-tetramethylpiperidinol sebacate according to the proportion of 1:1: 1.

The invention also provides a preparation method of the micro-foaming material, and the specific technical scheme is as follows:

a preparation method of a micro-foaming material comprises the following steps of mixing the foaming master batch and micro-foaming matrix resin according to the mass ratio of 1-3: 100 is added into an injection molding machine for injection molding, and the conditions are as follows: the injection speed is 80-100mm/s, the injection pressure is 80-100bar, the injection time is 0.8-1.2s, the pressure is not maintained, and the cooling time is 7-9 s.

Based on the technical scheme, the invention has the following beneficial effects:

the foaming modifier is obtained by taking ferric nitrate as a heat absorbent and copper sulfate as a slow release agent and matching with a coating material, and is used for preparing foaming master batches and foaming materials. The foaming modifier is added with a heat absorbent to absorb heat synergistically, the slow release agent reacts at low temperature to absorb a small amount of gas decomposed from the foaming agent sodium bicarbonate, decomposes at high temperature to release gas again, and is matched with the heat insulation and coating of the coating agent, so that the initial decomposition temperature of the foaming agent is increased, the decomposition rate of the foaming agent is reduced, and the decomposition temperature interval of the foaming agent is widened. Meanwhile, the decomposition of the heat absorbent also generates gas, thereby improving the foaming ratio. The foaming master batch can be used for preparing a foaming material with high foaming efficiency, small pore diameter of a pore, no surface defects of air mark, material flower, peeling, layering and the like in appearance and high mechanical property.

Drawings

FIG. 1 is a schematic diagram showing the appearance of a microcellular foamed material prepared in example 1;

FIG. 2 is a schematic diagram showing the appearance of the microcellular foamed material prepared in example 2;

FIG. 3 is a schematic diagram showing the appearance of the microcellular foamed material prepared in comparative example 1;

FIG. 4 is a schematic diagram showing the appearance of the microcellular foamed material prepared in comparative example 2;

FIG. 5 is a schematic diagram showing the appearance of the microcellular foamed material prepared in comparative example 3;

FIG. 6 is a schematic diagram showing the appearance of the microcellular foamed material prepared in comparative example 4;

FIG. 7 is a schematic diagram showing the appearance of a microcellular foamed material prepared in comparative example 5;

FIG. 8 is a schematic cross-sectional view of a microcellular foamed material prepared in example 1.

Detailed Description

In order that the invention may be more readily understood, reference will now be made to the following more particular description of the invention, examples of which are set forth below. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. These embodiments are provided so that this disclosure will be thorough and complete. It is to be understood that the experimental procedures in the following examples, where specific conditions are not noted, are generally in accordance with conventional conditions, or with conditions recommended by the manufacturer. The various reagents used in the examples are commercially available.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

The foaming modifier comprises the following components in parts by weight: 1-5 parts of a slow release agent; 1-5 parts of a heat absorbent; 5-15 parts of a coating material; the slow release agent is selected from copper sulfate; the heat absorbing agent is ferric nitrate; the cladding material comprises a first layer of cladding material and a second layer of cladding material; the first layer of coating material consists of erucamide, stearic acid and zinc stearate; the second layer of coating material is generated by the reaction of hydroxyl polydimethylsiloxane, hydrogen-containing silicone oil and a platinum catalyst.

The foaming modifier absorbs a part of heat by using the heat absorbent, so that the heat acting on the foaming agent is reduced, and meanwhile, the slow release agent is used for absorbing gas by reaction at low temperature, and is applied to preparing foaming master batches under the action of releasing gas again by high-temperature endothermic decomposition, so that the decomposition temperature range of the foaming agent is widened, and the decomposition rate of the foaming agent is reduced. Meanwhile, gas is generated due to the thermal decomposition of the heat absorbent, so that the foaming efficiency of the foaming agent is improved.

Preferably, the foaming modifier comprises the following components: 2-3 parts of a slow release agent; 2-3 parts of a heat absorbing agent; 2-5 parts of a first layer of coating material; 2-10 parts of a second layer of coating material. More preferably, the foam modifier comprises the following components: 2.5 parts of a slow release agent; 2.5 parts of heat absorbent; 2.5 parts of a first layer of coating material; and 2.5 parts of a second layer of coating material.

Preferably, in the first layer of coating material, the mass ratio of erucamide to stearic acid to zinc stearate is (1-3): 0.5-1.5): 1. More preferably, the mass ratio of the erucamide to the stearic acid to the zinc stearate is (1.5-2.5): (0.8-1.2): 1. Further preferably, the mass ratio of erucamide, stearic acid and zinc stearate is 2:1: 1.

Preferably, in the second-layer coating material, the mass ratio of the hydroxyl polydimethylsiloxane, the hydrogen-containing silicone oil and the platinum catalyst is 1 (0.5-1.5) to (0.004-0.006). More preferably, the mass ratio of the hydroxyl polydimethylsiloxane, the hydrogen-containing silicone oil and the platinum catalyst is 1 (0.8-1.2) to 0.005. Further preferably, the mass ratio of the hydroxy polydimethylsiloxane, the hydrogen-containing silicone oil and the platinum catalyst is 1:1: 0.005.

Preferably, the viscosity of the hydroxy polydimethylsiloxane is less than 0.08 Pa/s.

The foaming master batch comprises the following raw materials in percentage by weight:

preferably, the foaming master batch comprises the following raw materials in percentage by weight:

more preferably, the foaming master batch comprises the following raw materials in percentage by weight:

further preferably, the foaming master batch comprises the following raw materials in percentage by weight:

preferably, the polyethylene is selected from one of high density polyethylene, low density polyethylene and linear low density polyethylene. More preferably, the polyethylene is a low density polyethylene. More preferably, the Mw/Mn of the low-density polyethylene is more than 5, and the melt index of the low-density polyethylene is more than or equal to 40g/10min at 190 ℃ under a 2.16kg load.

Preferably, the ethylene-based elastomer is selected from one of ethylene-butene copolymer, ethylene-octene copolymer, and ethylene-propylene-diene monomer rubber. More preferably, the vinyl elastomer is an ethylene-octene copolymer. More preferably, the melt index of the vinyl elastomer is not less than 30g/10min at 230 ℃ under a 2.16kg load.

Preferably, the foaming agent is sodium bicarbonate.

Preferably, the processing aid consists of an antioxidant, a light stabilizer and a metal deactivator. More preferably, the mass ratio of the antioxidant to the light stabilizer to the metal deactivator is: 2:1:1.

More preferably, the antioxidant is selected from one or two of hindered phenol antioxidant tetra [ beta- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionic acid ] pentaerythritol ester and phosphite antioxidant tris (2, 4-di-tert-butyl) phenyl phosphite; and/or the light stabilizer is a hindered amine light stabilizer bis-2, 2,6, 6-tetramethylpiperidinol sebacate; and/or the metal passivator is N, N' -bis [ beta- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionyl ] hydrazine.

The preparation method of the foaming master batch comprises the following steps:

1) mixing and stirring a foaming agent and a heat absorbing agent, adding a first layer of coating material, heating, adding a slow release agent, stirring, then adding hydroxyl polydimethylsiloxane and hydrogen-containing silicone oil, and stirring to obtain a mixture A;

2) putting polyethylene, vinyl elastomer, platinum catalyst, the mixture A prepared in the step 1) and processing aid into a mixer in proportion, mixing and stirring, melting and extruding in a double-screw extruder, and granulating to obtain the polyethylene-vinyl elastomer-platinum catalyst.

The preparation method of the invention coats the foaming agent, the heat absorbing agent and the slow release agent in advance by using the coating agent, and the coating agent plays a certain role in blocking heat transfer, so that in the short-time heat transfer molding process of resin material injection molding, a small amount of gas generated when the foaming master batch is heated is insufficient in expansion ratio to break the crosslinked silicon rubber shell and generate the gas from the master batch, thereby obviously improving the initial decomposition temperature of the foaming agent master batch and obviously reducing the decomposition speed of the foaming agent.

Preferably, the temperature of the heating in step 1) is 70-90 ℃. More preferably 75-85 deg.c. Further preferably 80 ℃.

Preferably, the melt extrusion temperature is 90-110 ℃. More preferably 95-105 ℃. Further preferably 100 ℃.

Preferably, the screw length to diameter ratio of the twin screw extruder is 30-40: 1.

Preferably, the rotating speed of the double-screw extruder is 400-450 r/min.

The micro-foaming material is prepared from any one of the foaming master batches and micro-foaming matrix resin; the mass ratio of the foaming master batch to the micro-foaming matrix resin is 1-2: 100; the micro-foaming matrix resin comprises the following components in percentage by weight: 65% of polypropylene, 15% of ethylene-octene copolymer, 20% of talcum powder and 0.6% of processing aid.

Preferably, the mass ratio of the foaming master batch to the micro-foaming matrix resin is 1-2: 100. More preferably 1: 100.

The preparation method of the micro-foaming material comprises the following steps of adding the foaming master batch and the micro-foaming matrix resin into an injection molding machine according to the mass ratio of 1-2:100 for injection molding, wherein the conditions are as follows: the temperature is 200 ℃ and 220 ℃, the injection speed is 80-100mm/s, the injection pressure is 80-100bar, the injection time is 0.8-1.2s, no pressure maintaining is performed, and the cooling time is 7-9 s.

Because the decomposition rate of the foaming master batch is low, the gas decomposed by the foaming agent still has good dispersion effect under the limited shearing dispersion capacity of the molten gel storage of the injection molding equipment, and the problems of large foam holes, foam hole breakage and gas overflow are avoided. Therefore, the foaming master batch prepared by the invention has the characteristics of high foaming ratio and small pore diameter of the pores, eliminates the appearance defects of gas marks, material flowers, peeling, layering and the like in the processing and forming of the micro-foaming material, and obviously improves the overall performance of the material.

Preferably, the temperature is 200-. More preferably, the temperature is 205-. Further preferably, the temperature is 210 ℃.

Preferably, the injection speed is 80-100 mm/s. More preferably 85-95 mm/s. Further preferably 90 mm/s.

Preferably, the injection pressure is 80-100 bar. More preferably from 85 to 95 bar. Further preferably 90 bar.

Preferably, the injection time is 0.8-1.2 s. More preferably 0.9-1.1 s. More preferably 1 s.

Preferably, the cooling time is 7-9 s. More preferably 8 s.

In the following examples of the present invention, the raw materials used are specifically as follows:

foaming agent: sodium bicarbonate.

Polyethylene: the low density polyethylene has Mw/Mn greater than 5 and melt index not less than 40g/10min at 190 deg.c and 2.16kg load.

Vinyl elastomer: an ethylene-octene copolymer having a melt index of not less than 30g/10min at 230 ℃ under a 2.16kg load.

Processing aid: the metal passivator is composed of an antioxidant, a light stabilizer and a metal passivator according to a mass ratio of 2:1:

the antioxidant is selected from a compound of hindered phenol antioxidant tetra [ beta- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionic acid ] pentaerythritol ester and phosphite antioxidant tris (2, 4-di-tert-butyl) phenyl phosphite;

the light stabilizer is hindered amine light stabilizer bis-2, 2,6, 6-tetramethyl piperidinol sebacate;

the metal passivator is N, N' -bis [ beta- (3, 5-di-tert-butyl-4-hydroxyphenyl) propionyl ] hydrazine.

In the micro-foaming matrix resin, the melt index of the polypropylene is more than or equal to 80g/10min at 230 ℃ under the load of 2.16 kg.

The ethylene-octene copolymer has a melt index of not less than 2g/10min at 190 ℃ under a load of 2.16 kg.

The present invention will be described in detail with reference to specific examples.