CN101215391B - Preparation method of chlorinated polyethylene modified nitrile rubber foam material - Google Patents

Abstract

The invention provides a preparation method of a CPE modified nitrile rubber foaming material, which is environment-friendly, low in cost and wide in application range. The method comprises the following steps: according to the mass parts, 100 parts of nitrile rubber and 10-100 parts of chlorinated polyethylene, 1-5 parts of vulcanizing agent, 1-3 parts of accelerator, 5-15 parts of main foaming agent and 1-8 parts of composite adjusting foaming agent are heated at 100-190 ℃ for 10-100 minutes to obtain the modified nitrile rubber (NBR) foam material. The method has the advantages that: the ozone resistance, heat resistance and aging resistance of the NBR foam material are obviously improved; the flame retardance, the wear resistance and the tensile strength of the NBR foam material are improved; the product cost of the NBR foam material is obviously reduced, and good production manufacturability is kept; the method has better environmental friendliness; the obtained modified NBR foaming material has good physical property and foam stability; the process is simple and easy to control.

Description

A kind of preparation method of chlorinated polyethylene modified nitrile rubber foaming material

technical field

The invention belongs to the technical field of chemistry and chemical engineering, and in particular relates to a preparation method of a chlorinated polyethylene (CPE) modified nitrile rubber (NBR) foaming material.

technical background

Sponge rubber is a kind of rubber with loose and porous structure, which has good resilience and flexibility; at the same time, it has efficient shock absorption, sound insulation and heat insulation performance, and is widely used in sealing, noise reduction, shock absorption and other aspects.

According to the different pore structures, sponge rubber can be divided into three types: open cell (combined cell), closed cell (single cell) and mixed cell; according to the selection of materials at the place of use, the variety of sponge rubber that can be manufactured such as natural rubber (NR), Neoprene (CR), Nitrile Rubber (NBR), Ethylene Propylene Diene Rubber (EPDM), Styrene Butadiene Rubber (SBR), Silicone Rubber (MQ), etc.

General-purpose nitrile rubber (NBR) is a copolymer of butadiene-(1,3) and acrylonitrile, known for its excellent oil resistance. It is not only widely used in the production of rubber elastomers, but also a good basic material for bulk sponge rubber products.

Since the sponge rubber product has a porous structure and a large surface area, it is easy to age, especially the double bond embedded in the nitrile rubber, and its ozone resistance and heat aging resistance are particularly poor. Therefore, the use of blended modified nitrile rubber is an effective method, which not only improves the weather resistance, aging resistance, oil resistance and wear resistance, but also significantly reduces the cost of raw materials, and improves the production process to a certain extent.

Based on the obvious effects that can be obtained by blending modified nitrile rubber, the second component materials that can be blended at present mainly include rubber and plastics (inorganic substances and fiber-filled modification are not described in detail here). For example:

Styrene-butadiene rubber (SBR) and nitrile rubber (NBR) have good compatibility, and their blended products not only improve cold resistance, but also reduce the cost. If 100 parts of nitrile rubber with high acrylonitrile content is used, and 20 parts of styrene-butadiene rubber is used, the problem of oil resistance of the blended vulcanizate can be reduced.

Natural rubber (NR) also has unsaturated double bonds, which is similar to the vulcanization system of nitrile rubber. When 20 parts of natural rubber is added, the vulcanized rubber not only maintains the original high strength, but also improves low temperature performance and production process performance.

Phenolic resins have good compatibility with nitrile rubber. For example, the nitrile rubber blended with 50 parts of phenolic resin has improved hardness, wear resistance and tensile strength, and improved insulation, heat resistance and molding process performance.

Polyvinyl chloride (PVC) is a general-purpose plastic, and it has become a polymer alloy with good physical properties when used together with nitrile rubber. It not only significantly improves the ozone heat aging resistance of nitrile rubber, but also improves the wear resistance, oil resistance, flame retardancy and processability.

The aforementioned rubber or plastic blended with nitrile rubber has been used as a practical product for vulcanized rubber elastomers for many years, but there are relatively few examples of application to foamed nitrile rubber. The most common one is NBR+PVC co- Mixed foam rubber.

Polyvinyl chloride (PVC) is a general-purpose plastic with good comprehensive properties. However, due to the hazards of vinyl chloride in the production process and the dioxin carcinogens formed by the disposal of waste PVC, its application prospects have been cast a shadow, especially in the context of the current global environmental protection. Although it has not been explicitly banned, but It has been included in the unpopular list by Japan and the European Union.

Contents of the invention

The purpose of the present invention is to provide a kind of preparation method of the CPE modified nitrile rubber foam material that is environment-friendly, low in cost and wide in application range.

The method of the present invention comprises the following steps: in parts by mass, using 100 parts of nitrile rubber plus 10 to 100 parts of chlorinated polyethylene, 1 to 5 parts of vulcanizing agent, 1 to 3 parts of accelerator, and 5 to 15 parts of main foaming agent 1 to 8 parts of compound regulator foaming agent, plasticized and kneaded; heated at 100 to 190°C for 10 to 100 minutes to obtain a modified nitrile rubber (NBR) foam material.

In the above formula, other auxiliary components can also be added according to the prior art.

The method of the present invention can adopt molding method and normal pressure method.

The specific steps of the molding method are as follows: take out the rubber material that has been plasticized and mixed according to the formula, and place it in the mold cavity; control the temperature of the flat vulcanizer at 110~170°C, the vulcanization pressure at 10Mpa, heat for 10~50 minutes, and quickly Open the mold to obtain the modified NBR foam material; if necessary, the material needs to be vulcanized at 190°C for 50 minutes.

The specific steps of the normal pressure method are as follows: the rubber material that has been plasticized and mixed according to the formula is formed into a sheet through an extruder, and then placed in an oven with different temperature zones of 100~180°C, and then removed from the oven after 40 minutes. Take out the modified NBR foam material.

Described vulcanizing agent can adopt prior art, as sulfur, or the peroxide of sulfur such as sulfur peroxide etc.

The accelerator can adopt existing technology, such as M, DM, CZ and so on.

Described main blowing agent can adopt prior art, as AC blowing agent etc.

The composite regulating foaming agent can adopt the prior art, such as one or more mixtures selected from the following materials: foaming agent H, OBSH, sodium bicarbonate and the like.

The invention aims at the foaming material of CPE modified NBR, and adopts chlorinated polyethylene (CPE) to replace polyvinyl chloride (PVC). The reaction monomer and production process of chlorinated polyethylene (CPE) are completely different from PVC. It has a saturated main chain structure, so it has good oil resistance, weather resistance, ozone resistance and flame retardancy. CPE products are in the form of granules or powders with a particle size of 15-60um, which is conducive to better and faster dispersion and uniformity during the blending and mixing process. With the adjustment of chlorine content, CPE can have the characteristics of rubber or plastic, so that the blending system with nitrile rubber can be adjusted in a wider range to develop specific performance and better meet some special requirements. use.

The inventive method has the following advantages:

1. Significantly improved the ozone resistance and heat aging resistance of NBR foaming materials;

2. Improve the flame retardancy, wear resistance and tensile strength of NBR foam material;

3. Significantly reduce the product cost of NBR foaming materials while maintaining good production processability;

4. Better environmental friendliness;

5. The obtained modified NBR foam material has good physical properties and cell stability;

6. The process is simple and easy to control.

Detailed ways:

Below in conjunction with embodiment, content of the present invention is described in further detail:

Step 1): Configure raw materials.

Comparative formula A

300g of CPE and 30g of chlorinated paraffin are pre-mixed at 60°C, and the resulting pre-mixture is plasticized on the mill with different roll pitches, and then 1000g of NBR is added in batches for blending, and small materials such as Sulfur 10g, stearic acid 20g, accelerator M10g, foaming agent AC50g, compound regulator foaming agent (foaming agent H+OBSH) 80g, channel carbon black 200g, mix evenly and thin the triangular bag 3-5 times, Film output with large roll distance.

Comparing Formula B

200g of CPE and 25g of chlorinated paraffin are pre-mixed at 70°C, and the resulting pre-mixture is plasticized on the open mill with different roll distances. Then add 2000g NBR in batches for blending and blending, and add small materials such as sulfur 50g, accelerator CZ40g, boric acid 50g, foaming agent AC300g, composite regulator foaming agent (foaming agent H+sodium bicarbonate) in two intervals 20g, anti-aging agent D20g, semi-reinforcing carbon black 600g, thin-pass triangular bag 3-5 times, large roll distance to output the sheet.

Comparative formula C

700g CPE and 180g DOP are premixed at 80°C, and the obtained premixture is plasticized on the open mill with different roll pitches, and then 700g NBR is added in batches for blending, and small materials such as sulfur 35g are added at two intervals to promote Agent DM 21g, stearic acid 50g, foaming agent AC 70g, composite regulator foaming agent (OBSH+sodium bicarbonate) 35g, channel carbon black 180g, thin pass triangular bag 3-5 times, large roll distance to discharge the sheet.

Step 2): heating. Heating is implemented in the following two forms.

1. Molding method

Foam example 1

Take 400g of comparative formula A, control the temperature of the flat vulcanizer at 110°C, and the vulcanization pressure at 10Mpa, heat for 50 minutes and open the mold quickly to obtain the modified NBR sponge rubber, and then vulcanize the foamed material at 190°C for 50 minutes. Its typical physical properties are: density 0.07g/cm ³ , tensile strength 0.4Mpa, elongation at break 130%.

Foam example 2

Take 400g of the comparative formula B, control the temperature of the flat vulcanizer at 170°C, and the vulcanization pressure at 10Mpa, heat for 10min and open the mold quickly to obtain the modified NBR sponge rubber. Its typical physical properties are: density 0.11g/cm ³ , tensile strength 0.5Mpa, elongation at break 100%.

2. Atmospheric pressure method

Foam example 3

Take the comparative formula C and pass it through an extruder to form a sheet, then place it in an oven with a partition temperature of 100~180°C (if a long oven is used, the minimum temperature is 100°C, and the maximum temperature is 180°C), heat for 40 minutes, and cool Put it aside to get the modified NBR sponge rubber. Its typical physical properties are: density 0.09g/cm ³ , tensile strength 0.6Mpa, elongation at break 90%.

Claims (3)

1. the preparation method of a chlorinated polyethylene modified butadiene acrylonitrile rubber foaming material is characterized in that comprising the steps:

1) according to the mass fraction, adopt 100 parts of paracrils to add 10～100 parts of chlorination polyethylene, 1～5 part of vulcanizing agent, 1～3 part of promotor, 5～15 parts of main foaming agents, 1～8 part of compound adjusting whipping agent plastifies mixing; Described main foaming agent is the AC whipping agent, and described compound adjusting whipping agent is selected from one of following or more than one mixing: blowing agent H, OBSH, sodium bicarbonate;

2) step 1) is plastified the mixing sizing material that finishes, in blocks by forcing machine, placed immediately in 100～180 ℃ of sectional bakers of differing temps, take out baker after 40 minutes and promptly obtain modified butadiene acrylonitrile rubber foaming material.

2. the preparation method of chlorinated polyethylene modified butadiene acrylonitrile rubber foaming material as claimed in claim 1 is characterized in that described vulcanizing agent is a sulphur.

3. the preparation method of chlorinated polyethylene modified butadiene acrylonitrile rubber foaming material as claimed in claim 1, it is one of following to it is characterized in that described promotor is selected from: M, DM, CZ.