JPS59221366A - Adhesive rod - Google Patents

Abstract

PURPOSE:To obtain an adhesive rod for the bonding of crosslinked polyolefin, composed of a water-crosslinkable polyolefin, applicable at a necessary amount to the required part in the manner of soldering, and suitable for the joining of pipes and mending of joint part in which the presence of excess adhesive causes the increase in the flow resistance. CONSTITUTION:The objective adhesive rod has a cross-sectional area of preferably 3-20mm.<2> and containing (A) a water-crosslinkable polyolefin (preferably a polyolefin derived from a medium or high-density PE having a density of 0.930-0.955 and a melt index of 0.2-3g/10min or a low or medium-density linear PE having a density of 0.920-0.935 and a melt index of 0.2-3g/10min) and if necessary, (B) preferably <=0.01pt.wt., based on 100pts.wt. of the component A, of an agent to highly promote the crosslinking of the polyolefin with water. EFFECT:Even a highly crosslinked polyolefin having a gel franction of >=90wt% can be bonded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to an adhesive rod suitable for adhering and connecting articles made of crosslinked polyolefin, particularly crosslinked polyethylene, such as pipes and sheets.

[Prior art]

The present inventors have previously developed an adhesive in which a water-crosslinkable olefin is dissolved or dispersed in an organic solvent such as silane. Although this adhesive has excellent performance in adhering crosslinked polyolefin articles, it has a relatively high viscosity, so it has the disadvantage that it is somewhat difficult to apply the optimum amount only to the required areas.

[Summary of the invention]

The present invention proposes an adhesive bar free from the above-mentioned drawbacks, and proposes an adhesive bar for adhesion to crosslinked polyolefin made of water-crosslinkable polyolefin.

[Specific embodiments of the present invention]

Various types of water-crosslinkable polyolefins are already known, and the water-crosslinkable polyolefin constituting the adhesive rod of the present invention is not any of these conventionally known water-crosslinkable polyolefins. It's okay. For example, one example is a water-crosslinkable polyolefin containing a silane compound having a hydrolyzable organic group and an ethylenically unsaturated group. This water-crosslinkable polyolefin is a polyolefin such as polyethylene, polyethylene, ethylene-propylene copolymer, ethylene-vinyl acetate copolymer, etc., the above-mentioned ethylenically unsaturated carbon compound, and a free radical generator. It can be manufactured using

In the above, typical examples of the ethylene unsaturated silane compound include vinyltriacetyldisilane, vinyltriethyldisilane, vinyltriacetyldisilane, etc., and examples of radical generators include dicumylperoxysilane, laurelperoxysilane, , peroxides such as dibutylpero+cyto, penlyylpero+cyto, di-t-butylpero-hydrocarbon, t-butylene-diproper-hydrocarbon, etc., a-no compounds such as alihisisobutyonitrile, aliisobutylvaleronitrile, etc. , conventionally known conventional ones can be used as appropriate.

Further, as another example of the water-crosslinkable polyolefin, water-crosslinkable polyolefin made of a copolymer of ethicine and the ethylacetically unsaturated silane compound described in JP-A No. 55-9611 is also available. 1 nofine can also be suitably used.

Among the above, water-crosslinkable polyethylene whose polyolefin is polyethylene, particularly, a density of 0930 to 095
5. Medium high density polyethylene with MI of 0.2 to 3.0 fI/10 min, density 0.920 to 0.935, MI02 to
A water-crosslinkable polyolefin obtained from a low-medium density linear polyethylene having a molecular weight of 3.0y710 minutes is particularly preferred since it has excellent adhesive strength to crosslinked polyolefins, especially crosslinked polyethylene.

The adhesive of the present invention contains an agent having an effect of promoting crosslinking of water-crosslinkable polyolefin with water, such as a silanol condensation catalyst, at a concentration of
01 to 1 part (by weight, same hereinafter) may be included. Silanol condensation catalysts include, for example, diptyltin dilauret, 1 soot acetate, 1 soot hydroxide, lead naphthenate, zinc hydroxide, or others as shown in British Patent No. 1,357,549. It is what was done.

However, the adhesive of the present invention containing the above-mentioned silanol condensation catalyst has drawbacks such as rapid crosslinking with water, so it must be stored under dry conditions, and quick action is required in the bonding operation.

Therefore, adhesives preferred in the present invention either do not contain any agents that are determined to have a water crosslinking promoting effect according to the criteria below (hereinafter, such agents are defined as high water crosslinking promoters), or they contain The blending amount is 100 parts of the water-crosslinkable polyolefin, especially below the O and O parts.
005 or less. With such an adhesive, water crosslinking of the adhesive progresses reliably even when the bonded parts are left at room temperature during storage, and the bonding strength gradually increases.

[Judgment criteria for water crosslinking accelerators]

Polyethylene 1 with density 0925-0960, M11-2
00 parts, 05 parts of dicumylperoxysilane, 20 parts of vinyltrimethoxydisilane, and 0.1 part of water crosslinking accelerator for the test substance.
of the composition in two O-ru at a composition temperature of 120
Mix for 10 minutes at ~140'C and then keep the resulting homogeneous mixture in the atmosphere at 150C for 5 hours. The gel fraction of the composition is then determined using ASTM D 2765 Method A. Those having a gel fraction value of 10% or more are determined to be high water crosslinking accelerators.

Some silanol condensation catalysts, such as diptyltin dilaurate, fall under the above-mentioned high water crosslinking promoter.

The adhesive of the present invention includes:
Various other agents such as antioxidants, colorants, temperature sensitive agents, color changing agents, etc. may be added.

The adhesive rod of the present invention may have a circular, rectangular or other irregular cross-section, and may have the thickness of each rod, but the cross-sectional area may range from 2205 to 50 mm, especially from 3 to 50 mm. 20 lungs is preferred.

Since the amount of adhesive per unit length of the cross-sectional area of less than 051+++12 is small, the adhesive application operation is inefficient. On the other hand, it is preferable to use the adhesive of the present invention by melting it using hot air, and in this case, if the cross-sectional area is larger than 50 -, it will take a long time to melt because of its large heat capacity, so it will also take a long time to melt the adhesive. Work becomes inefficient. The adhesive of the present invention has a number of
It is best to manufacture it to a length of several tens of centimeters and use it on site.

[Effects of the present invention]

A polyolefin made of polyethylene having a gel fraction measured by method A of ASTM D-2765 of at least 5 weight units, especially at least 10 weight units, is not crosslinked at all, even though it is a low degree of crosslinking. Compared to polyolefins, the melt adhesion properties are significantly lower, and therefore it is difficult to bond using conventional methods. Adhesion of highly crosslinked materials is also possible. In the present invention, when it is referred to as a crosslinked polyolefin, it is meant to be applied to a polyolefin having a gel fraction of at least 5% by weight, particularly at least 10% by weight or more.

The adhesive rod of the present invention is melted from its tip using heating means such as hot air, so that it can be applied in the required amount to the place where adhesion is required in the same way as soldering. It is useful for repairing pipe connections and connections where the presence of water causes flow resistance.

There is an advantage that crosslinking progresses more gradually and adhesive strength improves accordingly.

〔Example〕

Inner diameter 21 made of cross-linked polyethylene (gel fraction 80%)
A bevel of approximately one depth was provided on the outside of each connecting end of two pipes with an outer diameter of 27+II+11, and the two pipes were brought together, and then the density was 0925, mp.

Water-crosslinkable polyethylene J obtained at 119°C from a composition consisting of 100 parts of MI2 glued polyethylene, 2 parts of dicumylperoxysilane, and 20 parts of dinyltrimethyldisilane.
A round adhesive rod (outer diameter: 6 mm, length: 30 cm) made by the manufacturer was brought close to the groove, and the tip of the adhesive rod and the groove were simultaneously heated with hot air at approximately 300°C to remove the adhesive. The tip of the rod was melted to fill the groove with molten water-crosslinkable polyethylene, and then cooled.

A water pressure test sample was prepared with 60 pipes at both ends with the connection point in the center, and the internal pressure of the pipe was increased to 2 rJ per minute.
The sample was destroyed by increasing the pressure at a rate of K9/cyn.

Immediately after the connection work, it broke at the connection point at a water pressure of 44 cm and 97 cm, but after being left in the atmosphere for 2 months, where it seems that the gelation of the adhesive had progressed to the phase, the pipe body broke at a water pressure of 46 cm/C:m. Destroyed.

patent applicant Dainichi Nippon Electric Cable Co., Ltd. Yukio Aoyama as Shusha Kibaiba

Claims (1)

[Claims] 1. An adhesive rod for bonding crosslinked polyolefin made of water crosslinkable polyolefin. 2. The adhesive rod according to claim 1, wherein the water-crosslinkable polyolefin is water-crosslinkable polyethylene. 6. A patent claim in which the water-crosslinkable polyolefin does not contain any high water crosslinking accelerator, or the amount of the high water crosslinking accelerator is not more than jl+ 0.01 parts by weight per 100 parts by weight of the water crosslinkable polyolefin. range of first to second adhesive rods. 4. Adhesive rod according to claims 1 to 6, having a cross-sectional area of 0.5 to 50 mm, in particular 3 to 20 mm.