RU2393192C1 - Adhesive composition - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention relates to adhesive compositions based on chloroprene rubber and can be used in the rubber industry when gluing together vulcanised rubber. The adhesive composition contains polychloroprene rubber nairit NT, butylphenolformaldehyde resin 101 K, thiuram, zinc oxide, magnesium oxide, a modifier and an organic solvent which is a mixture of ethylacetate and petroleum solvent. The modifier used is methylphosphite borate. Components of the composition are in the following ratio in pts. wt: polychloroprene rubber nairit NT - 100.0, butylphenolformaldehyde resin 101 K - 90.0, zinc oxide - 5.0, magnesium oxide - 12.0, thiuram - 2.0, said organic solvent - 800.0, methylphosphite borate - 10.0-30.0.

EFFECT: invention increases strength when gluing together vulcanised rubber based on different types of rubber.

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 acetaldehyde and acetanaphthene and 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 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 adhesive 88HT (TU2252-033-45539771-2000), which includes (parts by weight): polychloroprene rubber nairit NT - 100.0, butylphenol formaldehyde resin 101K - 90.0, zinc oxide 5.0, magnesium oxide 12.0, thiuram 2.0 and an organic solvent 800.0. As a solvent, a mixture of nephras and ethyl acetate in a percentage ratio of 50:50 is used.

However, the specified adhesive composition (although it is widely used because of its low cost) does not provide a sufficiently high strength when bonding vulcanized rubber (the achieved shear strength when bonding vulcanized rubber based on polyisoprene rubber (SKI-3) does not exceed 0.61 MPa )

The objective of the invention is the development of the composition of the adhesive composition having increased strength when bonding vulcanized rubbers based on various rubbers with each other and fire resistance.

The technical result is to increase the strength when bonding vulcanized rubbers based on various rubbers with each other.

The technical result is achieved by the fact that the adhesive composition, including polychloroprene rubber, Nairit NT, butylphenol formaldehyde resin 101K, thiuram, zinc oxide, magnesium oxide, an organic solvent, which is a mixture of ethyl acetate and nephras, and it additionally contains methylphosphate borate in the following ratio components, wt. h .: polychloroprene rubber nairit NT - 100.0, butylphenol formaldehyde resin 101K - 90.0, thiuram - 2.0, zinc oxide-5.0, magnesium oxide - 12.0, the indicated organic solvent is 800.0, methyl phosphite borate - 10.0-30.0.

Polychloroprene rubber nairit NT (TU-601781-73) is the main film-forming in adhesive adhesives.

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

Vulcanizing group: zinc oxide (zinc white), 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 443-76).

Methylphosphite borate is a viscous unpainted liquid, readily soluble in water, dimethylformamide, acetone, alcohols (US Pat. No. 2190697). Widely known as a combustion inhibitor.

When used as a modifier of the specified borate methylphosphite significantly increase the adhesive properties of the adhesive composition. This occurs due to an increase in the content of functional groups in the adhesive composition. As a result of the interaction of methylphosphite borate with a polychloroprene rubber macromolecule, an increase in the concentration of polar groups and the formation of additional chemical bonds contribute to an increase in the mobility of the polychloroprene macromolecule and deeper diffusion of its sections deeper into the surface of the vulcanizate. This explains the increase in strength when bonding vulcanized rubber to each other.

The adhesive composition is prepared as follows.

First, a rubber mixture is prepared (a mixture of Nairite NT, magnesium oxide, zinc oxide, thiuram) 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 the solvent, together with the other ingredients of the adhesive composition, with butylphenol formaldehyde resin, methylphosphite borate, 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 the specified modifier 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 88HT nairite glue prepared in a known manner (TU-2252-033-45 539771-2000), including polychloroprene rubber Nairit NT, 101K butylphenol formaldehyde resin, thiuram, zinc oxide, magnesium oxide and an organic solvent, the calculated amount is added , and mix the contents of 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 beige liquid. The glue is technological, it is well applied to the surface of rubber. Various contents of methylphosphite borate were investigated (Table 2).

The declared limits of the modifier 10.0-30.0 are 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), ethylene propylene rubber (SKEPT-40), butadiene nitrile rubber (SKN-18) and chloroprene rubber (Neoprene) are given 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. The fire resistance of the adhesive composition was determined by the method of determining resistance to burning (GOST 28157-89) by preliminary casting it on a flat glass surface and subsequent drying at room temperature for one day to a constant weight.

The data are presented in table 2, which shows that the best results were obtained using the composition of compositions 2 and 3.

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 glue on the prepared surface, drying of the adhesive film at room temperature (20 ° C) for 1-2 minutes, after which the adhesive surfaces were tightly pressed.

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 SKN-18 according to the prototype is 0.46 MPa, and using the proposed modifier 1.39 MPa.

Thus, as can be seen from table 2, when used in the proposed adhesive composition within the specified limits, the strength during bonding of vulcanized rubber products based on various rubbers increases, which is due to the participation of this modifier in increasing the adhesive properties of the adhesive.

We found that the reason for the increase in the adhesive characteristics of the adhesive composition is not only an increase in the concentration of polar groups when a modifier is introduced into the composition, but also the formation of additional chemical bonds during the interaction of this modifier with mobile allylic chlorine atoms in polychloroprene rubber macromolecules, which leads to an increase in the density of the spatial network and, apparently, to hardening the adhesive film.

We found that the reason for the increase in the adhesive properties of adhesive compositions is an increase in the concentration of polar groups when a modifier is introduced into the composition, as well as the formation of additional chemical bonds during the interaction of this modifier with mobile allylic chlorine atoms in the polychloroprene rubber macromolecules, which leads to an increase in the density of the spatial network and, apparently to hardening the adhesive film.

Table 1 The content of components, wt. hours Component in composition one 2 3 Prototype
glue 88НТ Polychloroprene rubber Nairit NT one hundred one hundred one hundred one hundred Butylphenol formaldehyde resin 101K 90 90 90 90 Tiuram 2 2 2 2 Zinc oxide 5 5 5 5 Magnesium oxide 12 12 12 12 Organic solvent (a mixture of ethyl acetate and nefras in a percentage of 50:50) 800 800 800 800 Methyl Phosphite Borate 10.0 20,0 30,0 -

table 2 Substrate Type Shear Strength, MPa Metric for composition Prototype
glue 88НТ one 2 3 SKI-3 0.69 0.94 1.13 0.61 SKEPT-40 1,08 1.27 1.23 0.99 SKN-18M 0.89 1.01 1.39 0.46 Neoprene speaker 0.80 0.98 0.92 0.73 Fire resistance of the adhesive composition - s / fade out s / fade out s / fade out burns

The technical and economic effect obtained from the use of the adhesive composition is that its application can significantly improve the quality of fastening of vulcanized rubber products based on various rubbers, and increase the fire resistance of the adhesive composition.

Claims (1)

An adhesive composition including polychloroprene rubber Nairit NT, butylphenol formaldehyde resin 101K, thiuram, zinc oxide, magnesium oxide, an organic solvent, which is a mixture of ethyl acetate and nefras, characterized in that it additionally contains methyl phosphite borate in the following ratio of components, wt. hours:
Polychloroprene rubber Nairit NT 100.0 Butylphenol formaldehyde resin 101K 90.0 Tiuram 2.0 Zinc oxide 5,0 Magnesium oxide 12.0 Specified Organic Solvent 800,0 Methyl Phosphite Borate 10.0-30.0