JP2810917B2 - Organic peroxide compound and method for producing modified plastic using the same - Google Patents

Description

The present invention relates to an organic peroxide compound and a method for producing a modified plastic having an improved melt flow index (hereinafter abbreviated as MFI) using the same.

(Prior art) There are very many types of thermoplastics, such as polyolefins represented by polyethylene and polypropylene, polyvinyl compounds represented by polyvinyl chloride and polyvinyl acetate, and polyamides represented by nylon. They are used for different purposes. By the way, in these thermoplastics, when an appropriate amount of an organic peroxide is blended and heat-treated, the crosslinking reaction takes precedence and the MF
A crosslinked plastic that causes a reduction or gelation of I,
Conversely, they can be categorized as either collapsible plastics, in which polymer chain cleavage is preferred and leads to an increase in MFI.
Examples of the former are polyethylene (hereinafter abbreviated as PE), polyvinyl chloride (hereinafter abbreviated as PVC) and polyvinyl acetate (hereinafter PVAC).
), Ethylene-vinyl acetate copolymer (hereinafter abbreviated as EVA) and the like, and the latter is polypropylene (hereinafter abbreviated as PP), polyisobutylene, poly-α-methylstyrene and the like. The organic peroxide dispersed in the plastic generates a radical by heating, and the radical extracts a hydrogen atom from a polymer chain to generate a polymer radical. Whether this polymer radical causes a crosslinking reaction or whether the polymer chain is cleaved by β-cleavage is considered to be based on the inherent properties of each plastic.

Then, utilizing this unique property, plastic MF
Improvements to I have been made. For example, in PE or EVA, crosslinking is carried out by blending an appropriate amount of an organic peroxide and treating it at an appropriate temperature in order to improve tensile properties, melt tension, heat resistance, and the like, thereby reducing MFI. On the other hand, in PP, a method of increasing the MFI using an organic peroxide has been put to practical use in order to improve the fluidity at the time of molding.

By the way, since the addition amount of the organic peroxide used for improving the MFI of such a plastic to the plastic may be small, uniform dispersion in the plastic is an important factor. That is, if the dispersion of the organic peroxide in the plastic is not uniform, in the case of a crosslinked plastic, the crosslinking reaction partially proceeds excessively, causing gelation, or in the case of a collapsed plastic, the flowability is large. Variations occur.
In order to uniformly disperse the organic peroxide in the plastic, a method of preliminarily diluting the organic peroxide with a filler such as calcium carbonate, silica powder, or clay, and then adding the resulting dispersion to the plastic is generally performed. ing. Alternatively, in applications where the aforementioned fillers cannot be used, the organic peroxide is mixed with plastic pellets or powder to form a low-concentration compound, or the plastic is melted and the organic peroxide is added to form a master batch. A method of making and adding the compound or masterbatch to a plastic and dispersing it has been put to practical use. Such a method increases the apparent amount of addition as compared with the case where the organic peroxide is added as a pure product, so that the dispersion is performed uniformly and the amount of addition is easily adjusted.

(Problems to be Solved by the Invention) Molding of thermoplastics is usually carried out by heating and melting the plastics. In order to prevent the plastic from deteriorating due to heat during molding, and to prevent the molded product from being deteriorated by oxygen, ozone, sunlight, heat, etc. when used for a long period of time, various antioxidants, ultraviolet absorbers, etc. Of additives are added to the plastic. Some of these additives are added during the production of thermoplastics and some are added during molding. Two or more additives may be used in combination. However, of these additives, antioxidants and ultraviolet absorbers have the property of decomposing peroxides added in plastics and trapping free radicals, so they are added when improving the MFI of plastics. There is a problem that it reacts partially with the organic peroxide to be produced. As a result, the MFI is not sufficiently reduced in a crosslinked plastic, and coloring and disintegration of a disintegrating plastic are particularly problematic in coloring and generation of odor. or,
Even when a plastic-based organic peroxide masterbatch is produced, there is a problem that the organic peroxide partially reacts when the organic peroxide is melted and mixed with the plastic. Even if such a master batch is added to a plastic and subjected to a melt-mixing process, the MFI cannot be sufficiently improved. In order to solve these problems, Japanese Patent Application Laid-Open No. 63-101438 discloses a method using a compound in which an organic peroxide is previously adsorbed on zeolites, but since zeolites have a high pH, The reaction between the organic peroxide and the above-mentioned additive is apt to occur, and depending on the type of the additive, coloring and odor are remarkable and cannot be put to practical use. Although a very limited variety of additives can be used, they have the disadvantage of not being versatile.

The problem to be solved by the present invention is, firstly, in a method for producing a modified plastic having an improved MFI of plastic using an organic peroxide, without being affected by additives such as antioxidants, Secondly, it is an object of the present invention to provide a method for producing a modified plastic having no odor, and secondly, in a process of producing a masterbatch by melting and mixing an organic peroxide with a plastic, the production method having no influence on the masterbatch. It is to provide.

(Means for Solving the Problems) The present inventors have found that the problems described above can be solved by using silica to which an organic peroxide is adsorbed, and have completed the present invention. That is, the present invention provides (1) an organic peroxide compound, which is obtained by adsorbing an organic peroxide onto silica having an adsorbing ability.

(2) A method for producing a modified plastic, which comprises blending the organic peroxide blend according to claim 1 with a plastic and treating it with heat.

I will provide a. When the organic peroxide blend of the present invention is blended into a thermoplastic and treated under appropriate temperature conditions, the MFI of the plastic is significantly improved without being affected by various additives added to the plastic. You. In addition, when the organic peroxide compound of the present invention is added to a molten plastic to form a masterbatch, and the masterbatch is mixed with the plastic and treated under an appropriate temperature condition, the masterbatch is treated with an organic solvent. The peroxide formulation is characterized in that the MFI of the modified plastic after treatment is significantly improved without any effect and that no colored odor is generated. Avoid the reaction between organic peroxides and plastic additives, as the diluents used in the past, such as calcium carbonate, silica powder, and clay, simply function to improve the dispersion of organic peroxides in plastics. However, in the organic peroxide formulation of the present invention, since the organic peroxide is adsorbed on silica and the pH of the adsorbable silica is around 7, other additives usually added to plastics are used. And reacts quickly with plastics to improve MFI significantly and efficiently. Even when a masterbatch is made by melting and mixing an organic peroxide with a plastic, if a masterbatch is made using a conventional diluent, it always reacts with the plastic and the MFI
However, the organic peroxide formulation of the present invention hardly changes the MFI of the masterbatch, and can be said to have a completely new function that cannot be found in conventional products.
Any silica having pores can be used as the silica having adsorptivity used in the present invention, and whether or not an organic peroxide has been adsorbed can be known by the presence or absence of heat of adsorption at the time of mixing. Specific examples of the silica having an adsorbing ability include Mizusuka Sorb S-1 and S-Smith manufactured by Mizusawa Chemical Industry Co., Ltd.
2, S-3, BH-30 and the like.

The organic peroxide used in the present invention may be either an aliphatic one or an aromatic one.
The above are preferred. For example, methyl ethyl ketone peroxide, ketone peroxides such as cyclohexanone peroxide, benzoyl peroxide, 2,
4-dichlorobenzoyl peroxide, diacyl peroxides such as lauroyl peroxide, t-butyl hydroperoxide, cumene hydroperoxide, hydroperoxides such as 2,4,4-trimethylpentyl-2-hydroperoxide, Dicumyl peroxide, 2,5-dimethyl-2,5-di- (t-butylperoxy) hexane, 1,3-bis (t-butylperoxyisopropyl) benzene, t-butylcumyl peroxide, di- dialkyl peroxides such as t-butyl peroxide and 2,5-dimethyl-2,5-di- (t-butylperoxy) -hexyne-3; 1,1-di-t-
Butyl peroxy 3,5,5-trimethylcyclohexane, 1,1-di-tert-butyl peroxycyclohexane,
Peroxy ketals such as 2,2-di- (t-butylperoxy) -butane, 4,4-di-t-butylperoxyvaleric acid-n-butyl ester, t-butylperoxy-2- Alkyl peresters such as ethylhexanoate and t-butylperoxybenzoate; and percarbonates such as t-butylperoxyisopropyl carbonate. The organic peroxide content in the organic peroxide formulation of the present invention is preferably 1% to 70%, more preferably 5% to 40% (weight ratio). In the case of an organic peroxide that is liquid at room temperature, it is mixed with adsorbent silica at room temperature to be adsorbed, or in the case of an organic peroxide that is solid at room temperature, the mixture should be at or above the melting point of the organic peroxide. Do or
After dissolving in a solvent and mixing, the mixture is adsorbed on adsorptive silica by a method of removing the solvent to obtain the organic peroxide compound of the present invention. In order to adsorb organic peroxide onto adsorbent silica, a ribbon planter, paddle mixer, mix master, pony mixer, universal mixer, Nauta mixer,
A concrete mixer, an omni mixer, a V-type mixer or the like can be used. Note that the effect of the present invention can be obtained only when the organic peroxide is adsorbed on the adsorptive silica in advance and an organic peroxide compound is obtained. Does not provide the effect of the present invention. The amount of organic peroxide formulation added to the plastic is preferably from 50 to 100,000 ppm, more preferably from 100 to 500,000 ppm.

Specific examples of the plastic to be modified in the present invention include low-density PE (hereinafter abbreviated as LDPE), high-density PE, linear medium-low-density PE (hereinafter abbreviated as LLDPE), ultra-low-density PE, PVC, PP, and PV.
AC, EVA, polyisobutylene, poly-α-methylstyrene,
A thermoplastic plastic such as an ethylene-propylene block copolymer can be exemplified. The compounding of the organic peroxide compound into these raw material plastics is carried out using pellets or powders of the plastics, using a kneading machine such as a Banbury mixer, a Nauta mixer, a ribbon blender, a kneader, a Henschel mixer, or a method in which the raw material plastic is dissolved in a solvent. Alternatively, in the case of a solution dissolved in a plasticizer, it is blended by mixing using a mixer such as a kneader or a universal mixer. When the organic peroxide compound of the present invention is melt-kneaded in advance with the raw material plastic to form a master batch, the kneading machine or extruder such as a Banbury mixer, a screw mixer, or a kneader can be used.
The resulting masterbatch is incorporated into plastics in the manner described above and modified by heat treatment.

The conditions of the heat treatment after blending the organic peroxide compound of the present invention with the plastic, and the heat treatment after blending the master batch with the raw material plastic vary depending on the type of plastic and the processing machine used, but generally, Preferably
The time at 120 ° C. to 250 ° C. is suitably 1 minute to 15 minutes. For the heat treatment, a kneading machine such as a Banbury mixer, a screw type extruder, or a kneader, as well as a high-pressure press, a continuous crosslinking apparatus using steam, nitrogen, or an inorganic salt as a heat medium can be used if necessary. In the case of producing a modified plastic using the organic peroxide compound of the present invention, 2,6-di-t-
Antioxidants such as butyl-4-methylphenol, ultraviolet absorbers such as 2-hydroxy-4-methoxybenzophenone, solvents such as stearic acid and calcium stearate,
Fillers such as carbon black and calcium carbonate, dyes and pigments can also be used depending on the application. These additives,
There is no particular limitation on the timing of adding the compounding agent.

(Action) The organic peroxide compound of the present invention can efficiently improve MFI without being affected by additives of plastics and the like. When a master batch is prepared by melting and kneading the organic peroxide compound with plastic, the organic peroxide compound of the present invention has no effect on the master batch.
When the masterbatch is mixed with plastic and heat-treated, the MFI can be efficiently improved.

(Examples) Hereinafter, the present invention will be specifically described with reference to Examples, Comparative Examples, Application Examples, and Application Comparative Examples, but these do not limit the present invention.

Example A compound shown in Table 1 was added to a universal mixer equipped with a stirring blade.
No.1 ~ No.6 organic peroxide and adsorptive silica total 1000g
And mixed at room temperature for 20 minutes to prepare organic peroxide formulations No. 1 to No. 6 of the present invention. The temperature change during mixing was as follows.

Compound No. 7 to N shown in Table 1 in a 30 Nauta mixer
The organic peroxide of No. 11 and the adsorptive silica were added to a total amount of 10 kg and mixed at room temperature for 30 minutes to prepare organic peroxide formulations No. 7 to No. 11 of the present invention. However, since Parkadox 14 used in Formulation No. 8 was solid at room temperature, it was melted by raising the temperature of the Nauta mixer to 50 ° C. and mixed with adsorbent silica. The temperature change during mixing was as follows.

The organic peroxide formulation of the present invention generated heat due to adsorption.

Comparative Example Compound N shown in Table 2 was added to a universal mixer equipped with stirring blades.
o. 12-15 organic peroxides and fillers or zeolites were added in a total amount of 1000 g and mixed at room temperature for 20 minutes to make comparative formulations Nos. 12-15. The temperature change during mixing was as follows.

Compound No. 16 to N shown in Table 2 in a 30 Nauta mixer
o.18 organic peroxide and filler were added to a total amount of 10 kg and mixed at room temperature for 30 minutes to prepare comparative formulations No. 16 to No. 18. However, since Parkadox 14 used in Comparative Formulation No. 17 was a solid at room temperature, the temperature of the Nauta mixer was raised to 50 ° C. to melt and mix.

 The temperature change during mixing was as follows.

When zeolites were used, heat was generated by adsorption, but no heat was generated with fillers other than zeolites.

1) Kayabutyl D: di-t-butyl peroxide 2) Kayahexa AD: 2,5-dimethyl-2,5-di (t-butylperoxy) hexane 3) Kayahexa YD: 2,5-dimethyl-2,5 -Di (t-butylperoxy) hexyne-3 4) Kayacarone BIC: t-butylperoxyisopropyl carbonate 5) Trigosox 29: 1,1-di-t-butylperoxy-3,3,5-trimethylcyclohexane 6) Kayabutyl B: t-butylperoxybenzoate 7) Kayaester O: t-butylperoxy-2-ethylhexanoate 8) Parkadox 14: 1,3-bis- (t-butylperoxyisopropyl) benzene 9) Kayabutyl H: t-butyl hydroperoxide 14) Zeolam F-9: Zeolite manufactured by Tosoh Corporation 15) Molecular sieve 13X: Zeolite Union Carbide 16) Calcium carbonate: NS # 100 Nitto Powder Chemical Co., Ltd. 17) Silica: Nippon Seal VN-3 Nippon Silica Kogyo Co., Ltd. 18) Clay: ST Clay Shiraishi Calcium Co., Ltd. Application Examples 1-11 Application Comparative Examples 1-9 Two rolls were heated to 75-85 ° C. and EVA was wound. The organic peroxide compound of the present invention and the antioxidant shown in Table 3 were added and kneaded. Then, take 20 g of it and press it in a mold of 128 mm x 87 mm x 2 mm for 200
No treatment was performed at -10 ° C for 10 minutes. The MFI of the sample after the heat treatment was measured according to JIS-K-7210. For comparison, the same operation was performed using the compounds shown in Table 3 instead of the organic peroxide compound of the present invention. Table 3 summarizes the results.

From the results in Table 3, it is clear that the organic peroxide formulation of the present invention can improve the EVA MFI without being affected by antioxidants.

Application Examples 12 to 21 Application Comparative Examples 10 to 17 The kneading zone of the single screw extruder was set to 230 ° C. To the pp powder, add the organic peroxide compound of the present invention shown in Table 4, an antioxidant, and an ultraviolet absorber, and mix well at room temperature.
Extrusion was performed by a single screw extruder. The pp after the treatment was measured for MFI according to JIS-K-7210. The odor was determined by finely chopping the treated pp with scissors and smelling the odor. Regarding the presence or absence of coloring, pp after treatment is 128 m
After placing in a m × 2 mm mold and pressing at 170 ° C., two sheets of 2 mm thickness were stacked and visually judged.

For comparison, the same operation was performed using the compounds shown in Table 4 instead of the organic peroxide compound of the present invention. The results are summarized in Table-4.

From the results shown in Table 4, it is clear that the organic peroxide compound of the present invention efficiently increases the pp MFI without coloring or giving an odor even when ordinary additives are used in combination.

Application Examples 22 to 30 Application Comparative Examples 18 to 22 The temperature of the two rolls was raised to about 140 ° C., and LDPE was wound. LDP
E to calcium stearate 10phr, Tris (2,4
(Di-tert-butylphenyl) phosphite (5 phr) and the organic peroxide composition of the present invention shown in Table 5 were added and kneaded to prepare a master batch. The MFI of the master batch was measured according to JIS-K-7210. For comparison, the same operation was performed using the compounds shown in Table 5 instead of the organic peroxide compound of the present invention. The results are summarized in Table-5.

Application Example 31 Application Comparative Example 23 The temperature of the two rolls was increased to 75 to 85 ° C., and Application Examples 1 to 11
The EVA used in Application Comparative Examples 1 to 9 was wound. 10 phr of the master batch of Application Example 25, antioxidant MARKAO-60
Was added to 0.1 phr and kneaded. Take 20 g of the back and press 200 in a 128 mm x 87 mm x 2 mm mold.
Heat treatment was performed at -10 minutes. Of the sample after heat treatment
MFI was 0.92 as measured by JIS-K-7210. As a comparison, when the same operation was performed using the master batch of Application Comparative Example 20 instead of the master batch of Application Example 21, the MFI of the sample after the heat treatment was 1.90.
Met.

Application Example 32 Application Comparative Example 24 The pp powder used in Application Examples 12 to 21 and Application Comparative Examples 10 to 17 was applied with 10 phr of the master batch of Application Experimental Example 28 and an antioxidant B.
0.1 HT of HT and 0.2 phr of UV absorber Sumisorb 130 were added and mixed well at room temperature. 230 ° C in kneading zone of single screw extruder
As a result, a pp compound was charged and extrusion treatment was performed. The MFI of pp after the treatment was measured by JIK-K-7210.
Met. When the odor and the presence or absence of coloring were determined in the same manner as in Application Examples 12 to 21 and Application Comparative Examples 10 to 17, there was no odor and the hue was equivalent to the blank of Application Comparative Example 10. As a comparison, the same operation was performed using the master batch of Application Comparative Example 19 instead of the master batch of Application Example 19. As a result, the pp MFI was 1.74 after the treatment, and the color was yellow.

Application Example 33 Application comparative example 25 n-octadecyl-3- (3'-
0.15 phr of 5'-di-t-butyl-4'-hydroxyphenyl) propionate and 2.3 phr of the masterbatch of Application Example 27 were added and mixed at room temperature. The kneading zone of the single-screw extruder was set at 200 ° C., the LLDPE compound was charged, and an extrusion treatment was performed. The MFI of the extruded LLDPE was measured according to JIS-K-7210 and found to be 0.35 (measuring conditions 190 ° C / 2160g)
Met.

As a comparison, the same operation was performed using the master batch of Application Comparative Example 21 instead of the master batch of Application Example 27. The MFI after the extrusion treatment was 0.70. The MFI of the LLDPE pellet obtained by simply extruding the pellet was 0.78.

From the results of Table 5, Application Examples 31 to 33, and Application Comparative Examples 23 to 25, the organic peroxide composition of the present invention was obtained in a masterbatch stage for uniformly dispersing the organic peroxide.
Although the MFI is not changed, it is clear that the MPI of the treated plastic is efficiently improved. In particular, in the conventional compound, the organic peroxide reacts at the stage of the production of the masterbatch to lower the MFI, and thus the MFI of the processed plastic is not sufficiently improved.

(Effects of the Invention) According to the present invention, it has become possible to improve the MFI of plastics more efficiently without being affected by plastic additives. Further, the application range of the organic peroxide has been expanded, and it has become possible to reduce the amount of addition. Therefore, the industrial value is extremely large.

Claims (2)

(57) [Claims] 1. An organic peroxide blend comprising an organic peroxide adsorbed on silica having adsorptive ability. 2. A method for producing a modified plastic, comprising blending the organic peroxide blend according to claim 1 with a plastic and treating it with heat.