JPS5821437A - Transparent polyolefin plastic composition - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to a polyolefin plastic composition with good transparency.

BACKGROUND OF THE INVENTION Polyolefins, such as polyethylene and polyzolopyrene, are provided in the form of films, sheets, hollows, etc. as packaging materials, containers, etc., and are used for a wide range of purposes. However, since the transparency is not sufficient, it is not suitable in cases where it is desirable to be able to see through packaging materials or containers for cosmetics, foods, etc.

Therefore, attempts have been made to improve transparency by adding certain additives.

Examples of such additives include t-butylbenzoic acid or a salt thereof, low-molecular waxy polyethylene, and low-molecular waxy polypropylene. However, these additives are not sufficient to improve transparency and may impair the mechanical and chemical properties of the product.
There were problems such as insufficient miscibility with polyolefins.

US Pat. No. 44,016,118 discloses the use of dibenzylidene sorbitol to improve transparency and mold shrinkage. Also, US patent applicant 143,25
No. 8 (filed April 24, 1980) discloses an additive that can further improve transparency compared to dipene-clidensorbitol. In this case, the mechanical and chemical properties of the product will not be affected. These additives are diacetals of sorbitol in which the benzene ring of the aldehyde moiety is substituted with chlorine or bromine at the meta and y positions.

Although these diacetal-type compounds are superior to conventional ones in that they can improve the transparency of polyolefin plastics, they are not always sufficient to improve the transparency of polyolefin plastics without impairing the mechanical and chemical properties of the product. A method that could improve the properties was desired.

This invention was made in view of the above circumstances, and rather aims to provide a polyolefin plastic composition that can improve mechanical and chemical properties as well as further improve transparency. do.

That is, the polyolefin plastic composition according to the present invention comprises: a) a main component consisting of an M-shaped low density polyethylene polymer; b) an appropriate amount of sorbitol diacetal and aromatic aldehyde for imparting transparency; C) -) acetal A diacetal decomposition inhibitor in an amount capable of suppressing the decomposition of;

The diacetal of the present invention may be a condensate of sorbitol and benzaldehyde, such as dibenzylidene sorbitol, or a condensate of sorbitol and a substituted benzaldehyde. Since the sorbitol moiety is substituted with two aldehydes, individual diacetals may be mixed aldehydes, such as those containing one unsubstituted benzaldehyde substitution and one substituted benzaldehyde substitution, or two different diacetals. It may also contain a substituted benzaldehyde. Substituents used at the ortho, meta or para positions of substituted benzaldehyde include alkyl groups having 1 to 5 carbon atoms, hydroxy groups,
These include methoxy groups, mono- and dialkylamino groups, amide groups, fluorine, chlorine, bromine, etc. Preferred diacetals include dibenzylidene sorbitol, no-p-chlorobenzylidene sorbitol, no-m-chlorobenzylidene sorbitol, 0-pennolitene-0-p-chloropene credensorbitol, di-
m-bromobenzylidene sorbitol, bis(3,4-
(nochloropenzylidene) sorbitol and di-tolylidene sorbitol. The most preferred diacetal is diacetal.
The diacetal of the present invention, which is p-chlorobenzylidene sorbitol, can be obtained by the following method. A common method is to react 1 mole of D-sorbitol with 2 moles of aldehyde in the presence of an acid catalyst. The reaction temperature depends on the properties of the starting aldehyde, such as its melting point. The reaction medium may be aqueous or non-aqueous. A preferred method of preparing diacetals for use in the present invention is described in US Pat. No. 43,721,682. Although this US patent is limited to pencylidene sorbitol, it has been found that similar methods can be applied to substituted diacetals.

The diacetal of solbitol according to the invention prepared by the above method may contain small or significant amounts of monoacetals and triacetals as impurities. Although these impurities do not necessarily need to be removed before adding the diacetal to the polyolefin, their removal is preferable for product clarity. In this case, the diacetal is purified using a relatively non-polar solvent such as triacetyl. This can be done by removing. By removing impurities, the diacetal content can be reduced to at least 90, or even about 95.

The proportion of diacetal in the compositions of this invention is sufficient to improve the transparency of the composition, generally from 0.01 to 5% by weight, preferably from 0.1 to 2% by weight (based on the total weight of the composition). ). If the amount of diacetal is less than 0.01 parts by weight, the resulting composition may not have sufficient transparency. No particular advantage is obtained when the amount of diacetal exceeds about 2% by weight.

The polyolefin polymer used in the present invention is a linear low density polyethylene polymer (LLDPE), such as G-Rasin 7144 (manufactured by Union Carbide).
It is. LLDPE/rimer allows for the polymerization of ethylene using smaller amounts of fumonomer at lower pressures and lower temperatures than previously possible.
This was obtained as a result of research on a catalyst system that As a result, a product with fewer and shorter side chains and better durability than conventional high-pressure polyethylene resins can be obtained.

The catalyst systems used in the production of such polyolefin polymers are typically of the Ziegler-Natsuta type using titanium tetrachloride and trialkyl aluminum. In addition, other metals, such as magnesium chloride, could be added to give the polymer the desired properties. Further, the catalyst may be impregnated into a carrier such as silica. Such a catalytic system is described in patent application No. 43,220 (filed January 6, 1982 or U.S. patent application &163,959° June 30, 1980).
(Japanese). Other metals that can be used in this catalyst system include panazoum, copper, and zolconium.

When the polymerization reaction is complete, it is necessary to remove or deactivate at least a portion of the catalyst residue.

This is because catalyst residues from tobacco are acidic and can seriously impair the performance of the resin or the properties of the various stabilizers contained therein. For example, on the interaction of antioxidants and catalyst residues in polyolefins, Tech.
Pap, Tech.

Conf@Soc/Plastic Engineering.

A study was conducted in 1980.478.

Removal or deactivation (or deactivation) of catalysts or acidic substances
This can be carried out, for example, by treating the polymer raw material with alcohols, olefins, polyesters, esters, ammonia, phosphates, or steam.

These treatments inactivate harmful substances in the polymer by the following mechanism. That is, it sequesters metal ions through coordination, inactivates them, reacts with metal chlorides, neutralizes generated hydrogen chloride, or physically washes acidic substances. . Therefore, some catalyst residue is present, which reacts with the stabilizer and is directly or indirectly detrimental to the polymer.

This catalyst residue causes a reduction in the transparency effect of diacetal. This decrease in clarity occurs when the ash content is 500 ppm.
This is noticeable in the above polyethylenes. In such cases, decomposition of the diacetal is evident from the characteristic odor from the diacetal treated resin. This odor is due to aldehydes, which are the raw materials of Acecool.

Furthermore, aldehydes can be determined quantitatively from extraction of the polymer with a suitable solvent and analysis of the extracted material by liquid chromatography.

It has been found that by adding an additive (auxiliary additive) consisting of diacetal to a polyolefin with a large amount of catalyst residue, transparency is promoted more than when diacetal is used alone. It acts as an activator and plays a role in preventing acidic substances or metals in the polymer from promoting the decomposition of diacetal.

Diacetals are generally unstable in the presence of acids, especially in the presence of water (e.g. moisture from the atmosphere).As a result, this co-additive (hereinafter referred to as diacetal decomposition inhibitor) The amount that can sufficiently prevent the decomposition of
It is necessary to add 0.05 to 1.05% (based on the weight of the composition). Here, "1 disturbance" means delaying or reducing. This does not mean completely preventing or eliminating undesirable phenomena. It therefore means that such phenomena occur less often. .

There are two types of acids that promote this decomposition. All of these are molecules or ions that have -7 or less when dissolved in water, such as hydrogen chloride or Tl (IV), and can accept a pair of electrons from an electron-donating atom. be.

The presence of acid residues in some diolefins results in the need to use an acid 7-buter in conjunction with a diacetal.

This acid acceptor can be divided into several categories.

For example: (1) a substance that can modulate or sequester an acidic molecule or ion, thereby preventing this acid from participating in a reaction in an undesirable manner; (2) reacting with the acid to form a harmless salt; (3) A substance that can react with an acid to provide a neutralizing substance that no longer participates in the reaction.

This acid acceptor itself must not cause devitrification of the preolefin - this acid acceptor functions according to the above mechanism.

Examples of this class (1) are ninephosphates, calgenates, especially fatty acid salts, amines, especially aliphatic amines, alkanolamines, hindered amines (e.g. Ttn
uvin 770 (trademark)), salts of amino acids, polyalkylene glycols, phosphates, hydrogen phosphate (phosphine), hydroxycarbunyl compounds, nocal? Examples of complexes of the class (1) include those shown below.

A B C The above class (C) includes those that neutralize acids such as hydrogen chloride with amines and other bases. For example, it reacts as follows: HCt+(C4H,), N→(C4H,), N
"-HC't"" Class (3) above includes organometallic compounds that react with acids such as nixides, artenes, cyclic esters, and hydrogen chloride to yield harmless neutralizing compounds. Other examples include is an acid anhydride, a reactive alcohol such as benzhytrol.The mechanism of this class (3) is shown below.

t CH3CH=CH2+ HCt-=) CH, -CH-
CH.

HH (C4H?)2Sn(SC12H25)2+HC4→(
C4H9)2SnctcSC12H25)+ C,2H
The most preferred 25SH decomposition inhibitor is phosphite. For example, Wsmton 618 e 619 (trademark,
Borg Warner Corp.). This W@S·ton 618 has the following structure.

Weston 619 is structurally the same as 618 but additionally contains one triisopropynolamine. Other decomposition inhibitors include fatty acid salts such as calcium stearate; aliphatic amines such as octadecylamine; alkanolamines such as triethanolamine and triisoglono9olamine; and polyalkylene glycols such as polyethylene glycol and polypropylene glycol. ; crown ethers and nonionic surfactants. Other diacetal decomposition inhibitors include phosphates, amino acids, hydroxycarbunyl compounds, dirudenyl compounds, hydroxycardoic acids, and polyhydroxy compounds.

The composition of the present invention can be prepared by adding the desired amount of diacetal and diacetal decomposition inhibitor directly to the polymer, and then mixing by appropriate means.

A primer master mixture containing about 10% by weight of a diacetal decomposition inhibitor may be prepared in advance and mixed with the resin later.

It is also possible to add other additives, such as transparent colorants or plasticizers (eg dioctyl phthalate, dibutyl phthalate, dioctyl sepacate, dioctyl azobate), as long as they do not impair transparency. Note that the above-exemplified plasticizer actually improves the transparency of diacetal.

In addition, the diacetal may contain other conventional additives having a transparency improving effect, such as monobutylbenzoic acid and its salts, and low-molecular weight waxy polypropylene.

When such a product is applied, the diacetal according to the present invention should occupy at least 10 parts, preferably 25 parts or more, and some p should account for 50 parts or more in the transparency-improving composition. The remainder consists of other known clarifying agents, plasticizers, etc.

Since the composition according to the present invention can provide films, sheets, and hollow bodies with excellent transparency, mechanical strength, and chemical properties, it is suitable for packaging materials, containers, etc. for cosmetics and foods.Examples are as follows. However, the quantities are specifically based on the indicated keyhole quantity.

Example 1 A concentrate having the following composition was obtained using a laboratory mixer.

Linear low-density polyethylene (G-Resin 7144, trademark,
Uniston 619 2.51゜This concentrate was then added to G-Resin 7144 8959, and W@l@y
The mixture was stirred with a mixer at 1100 rpm for 5 minutes. This mixture was then extruded at 465°F and injection molded at 450'F to yield a 50 mil thick sheet.

The degree of haze was 47 as measured by A8TMD1003-61, "Haze and Photoconductivity of Transparent Plastics."

Example 2 Linear, low-density polyethylene (
The haze level of G-Reait+ 7144) was 97 degrees.

Example 3 When Wsstop 619 was removed from the composition of Example 1, the resulting product had a haze level of 97 degrees.

Examples 4 to 10 Example 1 except that the type of diacetal decomposition inhibitor was changed
The product was obtained by a similar method.

The type and amount of this decomposition inhibitor are shown in the table below.

Example M Decomposition inhibitor Concentration (4) Haze (a) 4 Calcium stearate 0.10
555 Octadecylamine 0.10
556 Toryisozoro/Gunol 0
．． 08 62 Amine 7 Crown Ether 0.10
39 (15-crown-5) 8 α-hexadecene 025 6
7 Exide 9 Thermolite 31” 025
4810 Tinuvin 770 025
40 (bis-2e 2 e 6 p 6-tetramethyl-4-piperidinyl heptapate) (Note) *Organotin stabilizer (manufactured by M&T Chemical Co., Jersey, USA).

Claims (7)

[Claims] (1) (a) linear low-density polyethylene as a main component; (b) diacetal of sorbitol and aromatic aldehyde in an amount sufficient to improve transparency; (,) an amount sufficient to suppress decomposition of the diacetal. A transparent-lyolefin plastic composition comprising: an amount of a diacetal decomposition inhibitor; (2) The composition according to claim 1, wherein the decomposition inhibitor is a sequestering agent. (3) Claim 1 in which the decomposition inhibitor is an acid neutralizer
Compositions as described in Section. (4) Zoacetal posipenzylidene sorbitol: "-P-chlorobenzylidene sorbitol:')-m
6-benzylidene-o-p-ri tetralopenzylidene sorbitol;
The composition according to claim 1, which is selected from bupmopenzylidene sorbitol; bis(3,4-dichlorobenzylidene) sorbitol, and di-tolylidene sorbitol. (5) The composition according to claim 4, wherein the diacetal is di-p-chlorobenzylidene sorbitol. (6) The metal ion sequestering agent is 9phosphate, carganate,
Claim 2, wherein the compound is selected from amines, amino acid salts, 4-realkylene glycols, phosphates, phosphines, hydroxycar-nyl compounds, dicargel compounds, I-lyhydroxy compounds, crown ethers, hydrazones, and hydrazine. Composition of. (7) The acid neutralizer is an amine, an alkene, a nyxide,
The composition according to claim 3, which is selected from strained cyclic esters, organometallics, acid anhydrides, and reactive alcohols.