RU2543181C2 - Adhesive composition - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: adhesive composition contains polychloroprene rubber nairit DP, butylphenol formaldehyde resin 101 K, water, zinc oxide, magnesium oxide, an organic solvent which is a mixture of ethyl acetate and nefras, crushed polycaproamide fibre 23 KNTS. Modified crushed polycaproamide fibre 23 KNTS is obtained by pretreatment thereof with nonequilibrium low-temperature plasma of high-frequency glow discharge of alternating current in a vacuum chamber for 2 minutes.

EFFECT: invention increases strength of gluing vulcanised rubber to each other.

2 tbl, 1 ex

Description

The invention relates to adhesive compositions based on chloroprene rubber, and can be used in the rubber industry for bonding vulcanized rubbers based on various rubbers to each other.

Known adhesive composition comprising chloroprene rubber, thiuram, zinc oxide, as a resin, the product of the joint condensation of phenol of acetaldehyde and acetanaphthene and a solvent (USSR Author's Certificate No. 1579920, class C09J 111/00, publ. 23.07.90). As a solvent, a mixture of ethyl acetate and gasoline is used.

However, this adhesive composition does not provide a sufficiently high strength when bonding products from vulcanized rubber.

Known adhesive composition comprising polychloroprene rubber, epoxy resin, low molecular weight butadiene nitrile rubber, tertiary amine, solvent (USSR Author's Certificate No. 685673, class C08L 11/00; Publ. 15.09.79).

However, this adhesive composition has low strength when bonding rubber products based on various rubbers.

Known adhesive composition comprising polychloroprene rubber, butylphenol formaldehyde resin, a copolymer of styrene and piperylene, rosin esterified with glycerol; pine rosin, diphenylguanidine, 2,2-dibenzothiazole disulfide, zinc oxide, magnesium oxide, organic solvent (US Pat. Russia 2028358, MKI ⁶ C09J 111/00, publ. 09.02.95).

However, the specified adhesive composition, although it has a similar composition, is intended for bonding products from ferrites.

Closest to the invention in technical essence is an adhesive composition comprising polychloroprene rubber Nairit DP, butylphenol formaldehyde resin 101K, water, zinc oxide, magnesium oxide, an organic solvent, which is a mixture of ethyl acetate and nefras, and it additionally contains a pre-chopped 23KNTS polycaproamide fiber (Pat. Of Russia 2435805, C09J 111/00, publ. 10.12.11)

However, the specified adhesive composition does not provide a sufficiently high strength when bonding vulcanized rubber.

Objective: the development of the composition of the adhesive composition having increased strength when bonding vulcanized rubber to each other.

The technical result is to increase the strength when bonding vulcanized rubber to each other.

The technical result is achieved by the fact that the adhesive composition including polychloroprene rubber Nairit DP, butylphenol-formaldehyde resin 101K, water, zinc oxide, magnesium oxide, an organic solvent, which is a mixture of ethyl acetate and nefras, pre-milled polycaproamide fiber brand 23 KNTS, using modified polycaproamide fiber grade 23 KNTS obtained by pretreatment with a nonequilibrium low-temperature glow plasma of the alternating current discharge in a vacuum chamber for 2 minutes, with the following ratio of components, parts by weight: polychloroprene rubber Nairit DP - 90.0, butylphenol formaldehyde resin 101K - 90.0, water - 3.0, zinc oxide - 5, 0, magnesium oxide - 11.0, the specified organic solvent - 800.0, modified chopped polycaproamide fiber brand 23KNTS - 1.0-5.0.

Polychloroprene rubber nairit DP (TU-6-01-1319-85) is the main film-forming in adhesive adhesives.

Butylphenol formaldehyde resin 101K (TU-60004691277193-97).

Vulcanizing group: zinc oxide (zinc white GOST 202-84), magnesium oxide (burnt magnesia GOST 844-79) were previously used in adhesive compositions (Kardashov D.A., Petrova A.V. Polymer adhesives. M: Chemistry, 1983 )

Organic solvent: a mixture of ethyl acetate (GOST 8981-78) and nefras (GOST 3840167109-92).

The crushed polycaproamide fiber of brand 23 KNTS - 187 with a tex-size of 1-3 mm is obtained by passing through an extruder.

To modify the chopped polycaproamide fiber of grade 23 KNTS, the processing method in a glow low-frequency discharge of alternating current (50 Hz) was used. Processing time 2 min.

When using modified crushed polycaproamide fiber of grade 23 KNTS in the adhesive composition, the adhesive properties of the adhesive composition are significantly increased. As a result of the modification of the fibers on their surface, the number of hydrophilic functional groups that improve the wettability of the fibers increases, which leads to their more uniform distribution in the adhesive film and, as a result, to an increase in adhesive and cohesive strength.

This explains the increase in strength when bonding vulcanized rubber to each other.

The modification of crushed polycaproamide fibers of the KNTS grade 23 was carried out by pretreating it in a nonequilibrium low-temperature plasma — in a glowing low-frequency discharge of alternating current (50 Hz). A special teflon electrode holder was placed in the vacuum reaction chamber, on which metal electrodes were mounted. In direct contact with the lower electrode, a special metal frame was placed on which the processed fibers were placed. The installation was pumped out to a pressure of 10 ^-2 Pa using a foreline pump, the pressure in the reaction chamber was monitored using a vacuum gauge. Then, purified air was injected through the inlet system to a pressure of 15-20 Pa and voltage was applied to the electrodes from an alternating current source. Power was supplied from the network through a step-up transformer, a current with a frequency of 50 Hz, a current of 100 mA was measured with an ammeter. The fiber processing time is 2 min (Gilman AB, Drachev A.I., Kuznetsov A.A., Lopukhova G.V., Potapov V.K. High-energy chemistry. 1997. V. 31. No. 2. S. 141).

The adhesive composition is prepared as follows. First, the rubber mixture 31С-1-ДП is prepared - a mixture of Nairite DP, magnesium oxide, zinc oxide (ЕТР 8857-91) in a rubber mixer for 10 minutes, while the temperature of the mixer gradually rises (as the components of the mixture are introduced) from 50 ° C to 85 ° C. After unloading the mixture at a temperature of 105 ° C, it is paged for 5 minutes. Then the heated rubber mixture with a part of the solvent (about 0.1 part of the total amount of solvent) is loaded into the glue mixer. The remaining amount of solvent, along with other ingredients of the adhesive composition, with butylphenol formaldehyde resin, water, modified chopped polycaproamide fiber of grade 23 KNTS, are loaded in portions into the adhesive mixer as the rubber mixture swells. The total adhesive mixing time is 4.5-5 hours, while the introduction of modified chopped polycaproamide fiber of grade 23 KNTS can be carried out after preparation of the adhesive composition based on the remaining components.

An example of the preparation of the adhesive composition. Into a glue mixer containing 88CA nairite glue prepared in a known manner (TU 381051760-89), which includes polychloroprene rubber Nairit DP, 101K butylphenol formaldehyde resin, zinc oxide, magnesium oxide, water and the indicated organic solvent, the calculated amount of modified ground microfiber 23 is introduced KNTS and mix the contents for 5-10 minutes until a homogeneous mass.

Get the adhesive composition 1-3, the compositions of which are shown in table 1. The glue is a light gray liquid. The glue is technological, it is well applied to the surface of rubber. Various contents of the modified crushed polycaproamide fiber of grade 23 KNTS were investigated (Table 2).

The stated limits of the modified chopped polycaproamide fiber grade 23 KNTS 1,0-5,0 due to the fact that with an increase or decrease in these dosages, the adhesive strength during bonding decreases.

Comparative tests of the strength properties of adhesive compositions for all variants of the claimed composition and prototype when bonding vulcanized rubber based on polyisoprene rubber (SKI-3), nitrile butadiene rubber (SKN-18M), ethylene propylene diene rubber (SKEPT-40) and chloroprene rubber (Neoprene rubber) in table 2. For comparative tests, 3 variants of the compositions were prepared (according to the method described in the example) and the composition of the prototype presented in table 1. The proposed compositions were tested for adhesive shear strength, achieved when kept under a load of 2 kg, at room temperature (20 ° C) within 24 hours.

Shear adhesion was determined using an MPC-250 tensile testing machine (RTM 1.2.126-88). The technology for bonding samples is as follows. One-time application of the prepared adhesive on the prepared surface, drying of the adhesive film at room temperature (20 ° C) for 1-2 minutes, after which the adhesive surfaces were pressed tightly.

As can be seen from table 2, the proposed adhesive compositions provide an increase in the strength properties of adhesive joints in comparison with the prototype. So the shear strength of the adhesive joint when bonding vulcanized rubber based on SKI-3 according to the prototype is 0.69 MPa, and using the proposed modifier 1.34 MPa.

Thus, as can be seen from Table 2, when using the modified crushed polycaproamide fiber grade 23 KNTS in the proposed adhesive composition, the strength during bonding of vulcanized rubber products based on various rubbers increases due to the participation of this modifier in improving the adhesive properties of the adhesive.

Table 1 Component The content of components in the composition, parts by weight one 2 3 prototype Polychloroprene rubber Nairit DP 90.0 90.0 90.0 90.0 Butylphenol formaldehyde resin 101K 90.0 90.0 90.0 90.0 Water 3.0 3.0 3.0 3.0 Zinc oxide 5,0 5,0 5,0 5,0 Magnesium oxide 11.0 11.0 11.0 11.0 Organic solvent (a mixture of ethyl acetate and nefras in a percentage of 50:50) 800,0 800,0 800,0 800,0 Crushed polycaproamide fiber grade 23 KNTS - - - 1,0 Modified chopped polycaproamide fiber grade 23 KNTS 1,0 3.0 5,0 -

table 2 Substrate Type Shear Strength, MPa Metric for composition Prototype one 2 3 SKI-3 1.34 1,61 1.14 0.69 SKN-18M 0.77 0.85 0.84 0.68 Neoprene speaker 0.99 1.22 0.92 1.20 SKEPT-40 0.76 0.85 0.65 0.67

We found that the reason for the increase in the adhesive performance of adhesive compositions is an increase in the cohesive strength of the adhesive film when introduced into the composition of modified crushed polycaproamide fibers of grade 23 KNTS, as well as their partial penetration into the surface layers of rubbers.

The technical and economic effect obtained from the use of the adhesive composition is that its use can significantly increase the strength when bonding vulcanized rubber to each other.

Claims (1)

Adhesive composition including polychloroprene rubber Nairit DP, butylphenol formaldehyde resin 101 K, water, zinc oxide, magnesium oxide, an organic solvent, which is a mixture of ethyl acetate and nefras, milled polycaproamide fiber brand 23 KNTS, characterized in that they use modified micronized milled polymeric CNTS obtained by pretreating it with a nonequilibrium low-temperature plasma of a glowing low-frequency discharge of alternating current in a vacuum chamber for 2 minutes, in the following ratio of components, parts by weight:
Polychloroprene rubber Nairit DP 90.0 Butylphenol formaldehyde resin 101K 90.0 Water 3.0 Zinc oxide 5,0 Magnesium oxide 11.0 Specified Organic Solvent 800,0 Modified chopped polycaproamide fiber grade 23 KNTS 1.0-5.0