JPS6018530A - Production of polyethylene molded article - Google Patents

Abstract

PURPOSE:To obtain a crosslinked PE molded article with a simplified process, by mixing PE with a vinylalkoxysilane added with a Lewis acid and a radical generator, and heating, kneading and molding the mixture. CONSTITUTION:A mixture of (A) PE, (B) a vinylalkoxysilane added with a Lewis acid [preferably 1/10-1/4mol of a lewis acid (e.g. BF3) is added to 1mol of a vinylalkoxysilane (preferably vinyltrimethoxysilane, etc.)] and (C) a radical generator (e.g. benzoyl peroxide, etc. in an amount of preferably 0.1-10pts.wt. per 100pts.wt. of the vinylalkoxysilane) is kneaded under heating, and molded to obtain a molded article of PE. The amount of the vinylalkoxysilane in the component B is preferably 0.5-5pts.wt. per 100pts.wt. of the component A.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing crosslinked polyethylene molded articles.

Conventionally, vinylalcoxins such as cyvinyltrimethoxychloride were added to polyethylene at the same time as 2-ditrines were generated.
Polyethylene is graft-polymerized in a molten state to prepare a crosslinkable polyethylene grafted with vinyl alkoxy 7-ran, and the cross-linkable polyethylene is treated with a 7-ranol condensation catalyst such as diptyltin di-2-crate and optionally. It is possible to produce a crosslinked polyethylene molded product by mixing it with ordinary polyethylene and shaping it using an appropriate molding machine such as an extruder, and then treating it with hot water etc. to advance the silane crosslinking reaction. It is being said.

However, in the above method, polyethylene <;
The proportion of vinyl alkoxylic 7-rans that craft HHc, that is, the effective grafting rate is low, at most 50
~ 60 strands, therefore, there is a disadvantage that the expensive vinyl alkoxylic acid is wasted and the production cost increases.Also, the remaining vinyl alkoxylic acid that has been effectively grafted onto the polyethylene is It is contained as an impurity in polyethylene in the form of monomer or cloxane condensate, and this affects the flow characteristics, crosslinking characteristics, etc. of grafted polyethylene, making it difficult to reproducibly produce crosslinkable polyethylene with stable quality. Well manufacturing is a major cause of difficulty and has become a trap. Furthermore, in the above method, there is a step of graft-polymerizing alcoquine to polyethylene to prepare crosslinkable polyethylene in the form of pellets, and a step of shaping the product into a product shape and then carrying out lanol condensation by hot water treatment, etc. is required, and the process is more complicated than that of normal polyethylene product manufacturing.

In view of the above-mentioned current situation, the present invention is advantageous in terms of cost and quality as it allows vinylalkoxysilane, which is used to impart crosslinking properties to polyethylene 7, to be grafted onto polyethylene at a good grafting rate. This was done with the aim of providing a method for manufacturing crosslinked polyethylene molded products that is not affected by impurities due to ungrafted substances and that is also simplified in terms of process.
The gist lies in a method for producing a polyethylene molded article, which comprises heating and kneading a mixture of polyethylene, vinylalcoquino 7-rane to which a Lewis acid has been added, and a radical generator, and molding it into a product shape.

The vinyl alkoxy 7-ran used in the present invention refers to a 7-ran compound having a structure in which a vinyl group and at least one alkoxy group are bonded to one silicon atom, and is preferably used in the present invention. Examples include vinyltriethoxyquino7rane, vinyltriethoxy7rane, vinyltris-2-methoxyethoxyethoxysilane, vinyltriphenoquino7rane, trivinylethoxy7rane, and the like.

Further, the Lewis acid used in the present invention refers to a Lewis acid in a broad sense that does not contain liberable hydrogen in its molecule,
For example [BF3, B Fs (OC2H1)2, A1c1
3, Znc12, jec13.5nc14, T i c
14th grade is mentioned.

The above-mentioned Lewis acids have a property that is added to the oxygen position of the alkokino group of vinylalkoxysilane. By adding a gaseous, liquid, or solid Lewis acid to 72% by an appropriate manual method and stirring uniformly, the reaction between the two proceeds even at room temperature, and the above adduct is easily produced. .

The effects of the present invention can be sufficiently exerted when the amount of the Lewis acid added to the vinyl alkoxylic acid 7 run ranges from / to /10 4 mol per 1 mol of the 7 run.

The production of the adduct is confirmed by measuring the nuclear magnetic resonance absorption (NMR) or infrared spectral absorption (IR) of the above-mentioned reaction product. This can be done by detecting that the absorption position of hydrogen in the alkokino group has shifted, and in IR, that the absorption wavelength of the 5t-0 bond has shifted.

Next, as the radical generator, paid peroxides such as benzoyl peroxide and dicumyl peroxide can be used, and those which decompose at the melting temperature of polyethylene to generate radicals are usually preferably used.

The trap for manufacturing polyethylene molded products according to the present invention is to mix the Lewis acid-added vinyl alkoxysilane prepared above and a radical generator into polyethylene, and to process this mixture using an extruder, injection molding machine, or other suitable machine. The product is supplied to a molding means, heated, kneaded, and molded into the desired product shape.The amount of radical generator used at this time is 0 parts by weight per 100 parts by weight of vinyl alkoxy 7 run used. .1 to 10 parts by weight, and the Lewis M1 to polyethylene is preferably in a quantitative range such that the amount of vinyl alkoxylic 7 run used is 0.5 to 5 parts by weight for 100 parts by weight of polyethylene. ．． Preference is given to applying additional vinyl alkoxylic 7ranes.

The polyethylene molded product obtained in this way is already crosslinked when it is heated, kneaded, and molded into the desired product shape, and if it is left in the air after being formed, crosslinking will progress further, causing no practical problems. Since the degree of crosslinking is approximately
In particular, conventional operations such as hot water treatment for performing 7-run crosslinking may be carried out. However, if necessary, the degree of crosslinking can be further increased in a short time by performing operations such as hot water treatment.

As described above, according to the method of the present invention, polyethylene K can be produced.

A crosslinked polyethylene molded product can be obtained all at once by mixing vinyl alphylene/furan to which a Lewis acid has been added and a radical generator, heating, kneading, and molding. Since alkoxy-77-ran has extremely high graft polymerizability to polyethylene, when these are heated and kneaded by the action of a radical generator, the Lewis acid-added vinyl alkoxy-77-ran graft-polymerizes to polyethylene, Furthermore, the grafted Lewis acid-added vinyl alkoxy-7-ranol activated by heating during molding initiates a cy-7-ranol condensation reaction due to the very small amount of water present in the resin, and this reaction triggers the molding purse string mechanism. It is presumed that this effect spreads in a chain reaction during the molding period after the molding process, resulting in crosslinking of the polyethylene molded product.

In addition, in the above, since the Lewis acid-added vinyl alkyl/furan is grafted onto epolyethylene with extremely high grafting efficiency, the amount of vinyl alkyl/furan remaining in the polyethylene is extremely small, and for this reason, the present invention The consumption of potassium permanganate for the polyethylene moldings produced by this method is significantly lower than the consumption levels of conventional alkoxy/carbohydrate/grafted polyethylene crosslinked polyethylene moldings.

The method for manufacturing the polyethylene molded product of the present invention is as described above, in particular, a mixture of polyethylene and a vinyl alkoxylic acid-added 7-ran and 2-di-hydrogen generator is heated and kneaded to form a product shape. Since it is characterized by molding, it is possible to produce crosslinked polyethylene molded products in an extremely simplified process. Compared to polyethylene molded products, the amount of impurities such as vinyl 7 run residual monomers contained in polyethylene is smaller, so products of superior quality can be obtained.

Next, the present invention will be explained in Example Kx.

In addition, in the following, parts mean parts by weight.

Example Vinyl Trimethoquine 777 B F3 (002
) Is ) 2 to 7221 mol of vinyl '10-17
．． Add dropwise in a molar range, stir and dissolve, 60
Vinyltrimethoxysilane B F3 (OC2H
5) Two adducts were prepared.

The formation of the above adduct was confirmed by subjecting the reaction product to NMR and IR. In NMR, the hydrogen position of the vinyl group remained unchanged, but the hydrogen position of the methquino group was shifted, and in IR, it was found that the hydrogen position of the vinyl group was shifted. Nine experiments were conducted to confirm that the absorption wavelength of the 5i-0 bond was shifted.

Dicumyl peroxide is added and dissolved in the above adduct at a ratio of 0.05 to 0.15 parts per part of the adduct, and the amount of vinyltrimethoxysilane used is 1 to 10 parts per loo part of polyethylene. The mixture was added and mixed in a quantitative ratio of 3 parts, supplied to an extruder, heated and kneaded and extruded, and formed into a pipe under the conditions of the extruder 7 cylinder temperature of 180 to 200°C and the mold temperature of 180°C.

All molded pipes had a smooth surface appearance.

The crosslinked gel fraction of the thus obtained pipes was measured for four pipes: one immediately after extrusion, one after 2 hours of extrusion, one heated to 95°C for 2 hours immediately after extrusion, and one heated to 95°C for 4 hours immediately after extrusion. , and the obtained pipe at 100℃
A hot water immersion test was conducted to examine the discoloration after immersion in hot water for 7 days and the tensile strength after 30 days immersion, and the permanganese potassium consumption 11k was measured for the obtained pipe.The results are shown in Table 1. It was as shown.

The method for measuring the crosslinked gel fraction and potassium permanganate consumption is as follows.

Crosslinked gel fraction: A sample piece was extracted with xylene at 120° C. for 24 hours, and the weight ratio of the unextracted resin to the sample piece was expressed in h.

Potassium permanganate consumption: Cut the obtained pipe into a length of 1 m, fill the pipe with distilled water, and heat it at 80°C for 2 hours.
After leaving it for 4 hours, the water inside was taken out and the amount of potassium permanganate consumed was measured using a conventional method.

Comparative Example 1 For comparison, the same procedure as in the above Example (1) was carried out, except that vinyl trimethoquinosilane to which no Lewis acid was added was used in place of the Lewis acid-added vinyltrimethoquinosilane used in the above Example. A pipe was manufactured and the pipe was subjected to i tests.The results are also listed in Table 1.

Table 1 Procedural Amendment (self-imposed July 13, 1988, Commissioner of the Japan Patent Office 2, Name of the invention: Process for manufacturing polyethylene molded products 3, Person making the amendment Relationship to the case Patent applicant Postal code: 530 Address: Osaka City Patent Department, 2-4-4 Nishitenma, Kita-ku, Tokyo
πL (03) 434-95524, Detailed explanation of the invention in the specification to be amended Contents of the amendment (1) In the specification, page 4, line 10, @ page 9, line 4, and page 9, line 9 , "BFx (OCtHs h J") [BF3・
Correct it as O(C*Hs)z J.

that's all

Claims (1)

[Claims] 1. A method for producing a polyethylene molded article O, which is characterized by heating and kneading a mixture of polyethylene, vinyl alkoxy 7 run with 1 Lewis acid added, and a radical generator, and molding it into a product shape.