HK1095114B - A method for manufacturing a high multiple foam of a thermoplastic elastomer composite - Google Patents

Description

High-power foaming manufacturing method of thermoplastic elastomer composite material

Technical Field

The present invention relates to a method for producing foamed material, in particular, it relates to a method for producing high-power foamed material with the characteristics of general rubber and plastic foamed material by using traditional processing and foaming equipment and adopting two-stage chemical bridging foaming method.

Background

The foaming material in the prior art can be divided into a plastic foaming material and a rubber foaming material according to different used raw materials, and although the two-stage chemical bridging foaming process of the foaming material and related products are quite mature, the application fields of the foaming material are different due to different material characteristics of the foaming material. Taking the existing plastic foaming material as an example, Ethylene Vinyl Acetate (EVA) or a mixture of EVA and Polyethylene (PE) as a main raw material, in a traditional two-stage chemical bridging foaming process for plastics, the mixture is first mixed by a kneader, then mixed by a double roller, cut into pieces with suitable size by a discharging machine, and then stacked and sent to a first stage hot-pressing mold for first foaming to obtain a pre-foamed blank, which is then placed into a second stage hot-pressing mold with another predetermined specification while hot, and then continuously foamed for the second time, so as to obtain the desired high-magnification plastic foaming material. The plastic foaming material has the advantages of easy molding into other finished products with complex shapes in a later-stage processing procedure, high buoyancy, high heat insulation, high buffering property and the like, so that the plastic foaming material is often applied to manufacturing products such as life buoys, surfboards, heat insulation pipes and the like, and has the defect of inconsistent elasticity and slip resistance.

As for the existing Rubber foaming material, the Rubber material such as polystyrene-polybutadiene (SBR for short) and Chloroprene Rubber (CR for short) is used as the main raw material, because in the traditional two-stage Rubber chemical bridging foaming process, the mixture is mixed by a kneader, then is mixed by double rollers, and is cut into pieces with proper size by a discharging machine, and the pieces are piled up and then are sent to a hot-pressing mould of the first stage for first foaming, but in the second stage foaming process, the pre-foaming blank obtained in the first stage foaming process is put into a long oven with conveying function while hot, and is continuously foamed for the second time under normal pressure, so as to manufacture the required high-magnification Rubber foaming material. Although the rubber foaming material can make up for the defects of the plastic foaming material and has better elasticity, slip resistance and compression resistance, the formula of the rubber foaming material is more complex and the environmental pollution is easily caused by material dust generated in the manufacturing process. In addition, the rubber foaming material is not only difficult to be formed into other finished products with complex shapes in the post-processing procedure, but also the generated waste material is not easy to be recycled, which has been a problem that the industry using the rubber foaming material is always faced with but can not be effectively solved for a long time.

Therefore, how to change the process and process to obtain a high-power foamed material having the characteristics of common rubber and plastic foamed materials, thereby effectively improving the characteristics and application fields of the foamed materials, is an important subject to be discussed herein.

Disclosure of Invention

In view of the above, the inventor of the present invention has developed the present invention based on years of practical experience and research, and the high-power foamed material prepared by the method of the present invention has high elasticity and slip resistance which are possessed by common rubber foamed materials, and has the advantages of simple formula, easy coloring, easy secondary processing and environmental protection, and recycling.

The invention aims to produce a brand-new high-power foaming material by using a thermoplastic elastomer composite material by using a traditional two-stage chemical bridging foaming technology and a traditional two-stage chemical bridging foaming device without greatly changing the existing process conditions.

The invention provides a high-power foaming manufacturing method of a thermoplastic elastomer composite material, which comprises the steps of respectively adding foaming agents and bridging agents with different functions into the composite material taking a thermoplastic elastomer as a base material, kneading and discharging the composite material by a traditional device to form sheet bodies with proper sizes, stacking a certain number of sheet bodies according to actual requirements, sending the sheet bodies into a hot-pressing mold of a first section for first-time compression-mold foaming, and sending the obtained pre-foamed blank into a hot-pressing mold of a second section or a long oven for second-time compression-mold foaming or normal-pressure foaming treatment while the pre-foamed blank is hot, so that the high-power foaming material can be manufactured.

The thermoplastic elastomer is made of Styrene (Styrene thermoplastic elastomer) materials (i.e., mainly Styrene materials), which include Styrene-butadiene-Styrene (SBS), Styrene-ethylene/butylene-Styrene (SEBS), Styrene-isoprene-Styrene (SIS), or Styrene-ethylene-propylene-Styrene (SEPS).

In the substrate of the present invention, the weight of the styrenic material is 50% to 100% of the total weight; wherein the weight of the foaming agent accounts for 5-25% of the total weight of the composite material, and the foaming agent is preferably an azo chemical foaming agent; the weight of the bridging agent accounts for 0.01-0.5% of the total weight, and the bridging agent is preferably diisopropylphenyl peroxide, 2, 5-tert-butyl peroxy-2, 5-dimethylhexane or sulfur.

The method comprises the steps of respectively putting the components of the thermoplastic elastomer composite material into a conventional device according to the preset weight percentage, kneading and mixing the components in the device at the temperature of between 90 and 130 ℃, and uniformly mixing the components; after being uniformly mixed, the components are sent into a double-roller sheet discharging device to be rolled for a plurality of times to form a sheet with required thickness, and then the sheet is sequentially cut into sheets with proper size by an automatic cutter; can be based onSelecting proper weight of sheet, stacking them together, placing them into hot-pressing mould, making said hot-pressing mould be at 140-180 deg.C and 90-250 Kg/cm²Under the pressure of (2), performing first hot pressing and foaming treatment on the stacked sheet bodies; then the foamed blank can be placed into the second stage hot-pressing mould with preset specification while it is hot, and the temperature of said second stage hot-pressing mould is 140-180 deg.C, and is 90-250 Kg/cm²Or putting the foaming blank into a long drying oven with a conveying function while the foaming blank is hot, and carrying out secondary foaming treatment on the foaming blank by the long drying oven at the temperature of 140-180 ℃ under normal pressure.

In the method, the thermoplastic elastomer composite material further comprises other high polymer materials, the weight of the high polymer materials accounts for 0-50% of the total weight, and the high polymer materials are preferably polystyrene-polybutadiene, polystyrene, ethylene-vinyl acetate copolymer, low-density polyethylene and ethylene propylene diene monomer rubber; the thermoplastic elastomer composite material can also comprise a foaming auxiliary agent (preferably zinc oxide or urea), and the weight of the foaming auxiliary agent accounts for 0 to 3 percent of the total weight; the thermoplastic elastomer composite may further contain stearic acid or zinc stearate, and may preferably further contain a coloring material, calcium carbonate and wood chips, to thereby prepare a desired highly foamed thermoplastic elastomer composite.

In a preferred embodiment of the present invention, the thermoplastic elastomer composite further comprises a functional compounding agent including an antistatic agent, a flame retardant or a reinforcing agent.

The high-power foaming material prepared by the invention not only has the characteristics of high elasticity and slip resistance possessed by common rubber foaming materials, but also has the advantages of simple formula, easy coloring, easy secondary processing, environmental protection, recycling and regeneration and the like possessed by common plastic foaming materials.

Drawings

FIG. 1: the process flow diagram of the invention.

Reference numerals:

kneading and mixing-101

Rolling to obtain sheet-102

First stage hot pressing foaming-103

Second stage hot pressing foaming-104

Foaming at atmospheric pressure-105

Detailed Description

The present invention will be described in detail below with reference to the accompanying drawings, but the present invention is not limited to the scope of the present invention.

The invention relates to a high-power foaming manufacturing method of a thermoplastic elastomer composite material, which comprises the steps of utilizing the composite material taking a thermoplastic elastomer as a base material, respectively adding foaming agents with different functions, bridging agents and other components, kneading and sheet discharging the composite material by a traditional device to form sheet bodies with proper size, stacking a certain number of sheet bodies according to actual needs, sending the sheet bodies into a hot pressing mold of a first section for first compression molding foaming, and sending the obtained pre-foamed blank into a hot pressing mold or a long drying oven of a second section for second compression molding foaming or normal pressure foaming treatment while the pre-foamed blank is hot to manufacture the foaming material with the foaming ratio of more than 15 times.

In the whole manufacturing process, referring to fig. 1, the invention completely adopts the traditional two-stage chemical bridging foaming process, utilizes the traditional kneading, sheet discharging and foaming device, and sequentially performs the kneading, sheet discharging and foaming treatment on the prepared thermoplastic elastomer composite material according to the following steps:

firstly, putting each component of the thermoplastic elastomer composite material into a kneader (kneader), a two-roll mixer (two-roll mill) or a Banbury mixer (Banbury mixer) according to a predetermined weight percentage, and uniformly mixing in the device at a temperature of about 90 to 130 ℃, namely step 101;

feeding the uniformly mixed thermoplastic elastomer composite material into a double-roller sheet discharging device, rolling the composite material, after rolling for a plurality of times to form a sheet with required thickness, sequentially cutting the sheet into sheets with proper size by an automatic cutter for later use, namely 102;

selecting proper amount or weight of sheet bodies according to actual requirements, stacking the sheet bodies together, placing the stacked sheet bodies into a hot-pressing mold at a first section, and enabling the hot-pressing mold to have a temperature of about 140-180 ℃ at about 90-250 kg/cm²The first hot pressing and foaming process is performed on the stacked sheets under the pressure of (3), and after a suitable time, the required pre-foamed blank can be manufactured in about 10 to 40 minutes depending on the size and thickness of the mold, i.e. step 103.

In the second stage of the foaming process of the present invention, the following steps are different depending on the adopted mold-pressing foaming or normal-pressure foaming process:

if a mould pressing foaming process is adopted, the foaming blank is put into a second-stage hot-pressing mould with a preset specification while the foaming blank is hot, and the second-stage hot-pressing mould is made to be at the temperature of about 140 to 180 ℃ and about 90 to 250Kg/cm²Under the pressure, the foaming blank is hot pressed and foamed for the second time, after a certain time, the required high-power foaming material can be produced in about 10 to 40 minutes according to the size and thickness of the mould, that is, step 104.

If the normal pressure foaming process is adopted, the foaming blank is put into a long oven with a conveying function while the foaming blank is hot, the long oven carries out secondary foaming treatment at the temperature of about 140-180 ℃ under normal pressure, after the treatment for a certain time, the required high-efficiency foaming material can be manufactured according to the size and the thickness of the foaming blank, generally about 10-30 minutes, namely 105 steps.

In a preferred embodiment of the invention, the thermoplastic elastomer composite comprises the following components:

(1) styrene-based thermoplastic elastomer: it is the base material of composite material, accounting for 50-100% of the total weight, and may be SBS, SEBS, SIS or styrene-ethylene-propylene-styrene material.

(2) Chemical foaming agent: about 5% to about 25% by weight of the total composition may be an azo-based chemical blowing agent.

(3) A bridging agent: about 0.01% to about 0.5% by weight of the total composition may be dicumyl peroxide (dicumyl peroxide), 2, 5-peroxy-tert-butyl-2, 5-dimethylhexane <2, 5- (tert-butyl peroxide) -2, 5-dimethylhexane > or sulfur.

The inventor utilizes the above components and the traditional two-stage chemical bridging foaming method to prepare the high-efficiency foaming material of the thermoplastic elastomer, and the high-efficiency foaming material has the following advantages through experimental verification:

(1) the invention can prepare a brand new high-power foaming material with the characteristics of rubber and plastic foaming materials by using the traditional two-stage chemical bridging foaming technology and device without greatly changing the process conditions.

(2) The high-power foaming material has a foaming ratio of more than 15 times and a foaming specific gravity of less than 0.07.

(3) The foaming thickness of the high-power foaming material can reach more than 50mm according to the thickness of a mould.

(4) The high-power (high-efficiency) foaming material prepared by the invention not only has excellent elasticity and slip resistance, but also has the characteristics of easy coloring, no vulcanized rubber odor and easy recovery and reuse, and can effectively increase the diversity of the application of the foaming material.

(5) The foaming material has excellent secondary processability in a later-stage processing procedure, can be easily processed and molded into a complex shape or a pattern, and is suitable for products needing embossing, transfer printing, laminating and other designs.

In addition, in the practice of the present invention, the composite material is not limited to the above components, and the following components can be selectively added to the composite material of the thermoplastic elastomer to produce the thermoplastic elastomer foam material of the present invention according to the intended function, characteristics or actual requirements:

(1) other high molecular materials: the components account for 0 to 50 percent of the total weight, and can be Polystyrene-polybutadiene (SBR), Polystyrene (PS), EVA, Low Density Polyethylene (LDPE), Ethylene Propylene Diene Monomer (EPDM) and other high polymer materials, so that the material characteristics of the foaming material are changed, and the foaming material can meet the actual requirement.

(2) Foaming auxiliary agent: the component accounts for 0-3% of the total weight, and can be zinc oxide, urea, etc., so as to promote foaming effect and speed.

(3) Other additives: the components comprise materials such as stearic acid or zinc stearate as processing aids, or materials such as pigments, calcium carbonate and wood chips as extenders, so as to change the material characteristics or the presented visual effect of the foaming material.

(4) Functional compounding agents: the component is determined by the required material function, and can be materials such as antistatic agent, flame retardant or reinforcing agent.

The above description is only a preferred embodiment of the present invention, and the scope of the right of the present invention is not limited thereto, and those skilled in the art can make appropriate changes according to the technical contents disclosed in the present invention without departing from the scope of the present invention.

Claims (13)

1. A high-power foaming process for preparing the composite material of thermoplastic elastomer includes such steps as adding foaming agent and bridging agent to the composite material with thermoplastic elastomer as basic material, mixing at 90-130 deg.C, kneading, pugging, rolling to become sheet, and cutting by automatic cutter;and selecting the sheet bodies according to actual needs, stacking the sheet bodies together, placing the stacked sheet bodies into a hot-pressing die at a first section, and enabling the hot-pressing die to be at a temperature of between 140 and 180 ℃ and between 90 and 250Kg/cm²Under the pressure of the pressure, carrying out first hot pressing and foaming treatment on the stacked sheet bodies to prepare a pre-foaming blank, and then sending the obtained pre-foaming blank into a hot pressing mould or a long oven of a second section for secondary die pressing foaming or normal pressure foaming treatment to prepare a high-power foaming material;

the thermoplastic elastomer takes a styrene material as a base material, and is measured according to the total weight of the composite material as 100 percent, wherein the styrene material accounts for 50 to 100 percent by weight, the foaming agent accounts for 5 to 25 percent by weight, and the bridging agent accounts for 0.01 to 0.5 percent by weight.

2. The method of claim 1, wherein the styrenic material is styrene-butadiene-styrene, styrene-ethylene/butylene-styrene, styrene-isoprene-styrene, or styrene-ethylene-propylene-styrene.

3. The method of claim 2, wherein the blowing agent is an azo-based chemical blowing agent.

4. The method of claim 3, wherein the bridging agent is dicumyl peroxide, 2, 5-t-butyl peroxy-2, 5-dimethylhexane, or sulfur.

5. The method of claim 1, further comprising placing the pre-expanded blank in a second hot press mold of predetermined dimensions while it is hot, and allowing the second hot press mold to set the temperature at 140 to 180 ℃ at 90 to 250Kg/cm²Under the pressure of (2), carrying out hot pressing and secondary foaming treatment on the foaming blank.

6. The method of claim 1, further comprising placing the pre-expanded blank hot in the elongated oven with a conveyor function, and subjecting the expanded blank to a second expansion process at a temperature of 140 to 180 ℃ under atmospheric pressure.

7. The method according to claim 5 or 6, wherein the thermoplastic elastomer composite further comprises other polymer materials, and the weight of the polymer materials accounts for 0 to 50 percent of the total weight.

8. The method of claim 7, wherein the polymer material is polystyrene-polybutadiene, polystyrene, ethylene-vinyl acetate copolymer, low density polyethylene, ethylene propylene diene monomer.

9. The method according to claim 5 or 6, wherein the thermoplastic elastomer composite further comprises a foaming aid in an amount of 0 to 3% by weight.

10. The method of claim 9, wherein the foaming aid is zinc oxide or urea.

11. The method of claim 5 or 6, wherein the thermoplastic elastomer composite further comprises stearic acid or zinc stearate.

12. The method of claim 5 or 6, wherein the thermoplastic elastomer composite further comprises a colorant, calcium carbonate, and wood chips.

13. The method of claim 5 or 6, wherein the thermoplastic elastomer composite further comprises a functional compounding agent comprising an antistatic agent, a flame retardant, or a reinforcing agent.