JPH02261863A - Resin composition - Google Patents

Abstract

PURPOSE:To prepare a resin compsn. which enables the whole scrap generated from it to be recovered and reused by compounding a thermoplastic resin, an ethylene-vinyl alcohol copolymer, an adhesive resin, and a silane-modified polyolefin resin in a specified ratio. CONSTITUTION:A resin composition comprising a thermoplastic resin; an ethylene-vinyl alcohol copolymer having an ethylene content of 20 to 60mol% and a saponification degree of the vinyl acetate component of at least 90%; an adhesive resin capable of adhering to said thermoplastic resin and to said ethylene-vinyl alcohol copolymer; and a silane-modified polyolefin resin, pref. vinylmethoxysilane or vinylethoxysilane, wherein the content of silicon corresponds to 0.0001 to 0.1wt.% of the total compsn.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Industrial Application The present invention provides a multilayer coextrusion molding of a thermoplastic resin and an ethylene-vinyl alcohol copolymer (hereinafter referred to as EVOH) having excellent gas barrier properties. Or, when reusing trim scraps and scraps that are generated during secondary molding, this occurs when the scraps are reused directly on the thermoplastic resin during the above multilayer coextrusion molding, or by providing one or more layers as a recovery layer. , no sagging on the membrane surface, no delamination whitening inside the collection layer, and no secondary enclosing (
The present invention relates to a resin composition that does not cause deterioration in transparency during stretching, thermoforming, etc.).

"L-Moxibustion Dotan" Laminates thermoplastic resin and EVOH to create films and sheets.
- Widely used for containers, cups, bottles, etc. However, when manufacturing the multilayer structure, especially when manufacturing cups and bottles, as much as 20 to 50% of scrap (
Scraps are generated, and the recovery and usability of the scraps is a major problem in terms of production costs. That is, in single-layer production, it is possible to return the scrap to the original extruder and reuse it, which is practiced by most manufacturers. When the multilayered scrap is put into the extruder on the original thermoplastic resin side, or using a scrap extruder,
Many attempts have been made to provide one or more scrap layers for reuse, but if the entire amount of scrap is reused, the finished product may have poor appearance (surface roughness, poor transparency, streaks), and the recovered layer may The product cannot be used as a product due to whitening and delamination. Therefore, it is currently difficult to collect and reuse all of the scrap.

To solve this problem, proposals have been made to change the shape of the screw, particularly the use of a reinforced screw in the kneading section, or to blend adhesive resins, in order to improve the mixability of scrap, but these proposals have not been effective enough. Not only this, but on the contrary, it has led to the frequent use of gels, etc., and has not been adopted.

On the other hand, regarding the method of blending silane-modified polyolefin with EV OH etc., Japanese Patent Application Laid-Open No. 611, 55412
However, simply blending the two did not solve the problem of coextrusion moldability (poor appearance, delamination). Furthermore, judging from the examples of the patent, the patent only describes a method for producing a gas barrier resin that can be melt-molded by plasticizing polyvinyl alcohol, and the patent only describes a method for producing a gas barrier resin that can be melt-molded by plasticizing polyvinyl alcohol. No technical ideas regarding improvement are recognized at all.

C9 is about to start - The present invention returns the entire amount of scrap generated by multilayer coextrusion molding of thermoplastic resin and EVOH to the original molding machine,
The object of the present invention is to provide a resin composition that can be recovered and reused.

01 Means for solving the problem The problem is solved by thermoplastic resin (A) and E V OH (B)
adhesive resin (C) that can adhere to both (A) and (B).
) and silane-modified polyolefin (D).

The present inventors have discovered that surface roughness, opacity, and delamination that occur during coextrusion molding occur when scraps of a multilayer structure of thermoplastic resin (A) and EVOH (B) are returned to the original molding machine and used for recovery. As a result of intensive consideration of measures to prevent the occurrence of abnormalities such as
) and the adhesive resin (C), it was found that abnormalities during molding were improved and a good molded product without the occurrence of cracks, gels, or bubbles was obtained, and the present invention was completed. I ended up doing it. That is, more specifically, (A)+
(B)+ (C), (A)+ (B)+ (D), (A
) Ten (B) blend system has little effect on improving abnormalities, but (A) + (B) + (C) Ten (D) shows an unexpected improvement effect at a specific composition ratio as described later. I understand. Furthermore, a salt containing at least one element selected from Groups I, II, and III of the Periodic Table, such as a metal salt of ethylenediaminetetraacetic acid, a hydrotalcite-based compound, or a higher fatty acid metal salt, is added to the composition. Alternatively, blending an oxide with (A) or (B) or (C) may be even more effective.
) or (D) a composition (A') blended with (E)
), (B'), (C゛) as (A) ten (B) + (c'
), (A) + (B' ) + (c), (A') + (B
) + (C), etc., it was found that there was a further improvement effect, and the present invention was completed. These matters are also clear from the examples described below.

In the present invention, the thermoplastic resin (A) includes particularly low water absorbency plastic resins such as polyolefin, polyester, polyamide, polystyrene, polycarbonate, polyvinyl chloride, etc., and one or more of these may be used simultaneously. It will be done.

Polyolefins include high-density, medium-density, and low-density polyethylene, vinyl acetate, acrylic esters,
Or polyethylene copolymerized with α-olefins such as phytene, hexene, and 4-methyl-1-pentene,
Ionomer resin, polypropylene homopolymer Polypropylene graft-polymerized with ethylene, polypropylene copolymerized with α-olefins such as ethylene, butene, hexene, 4-methyl-1-pentene, modified polypropylene blended with rubber polymer, poly1 -butene, poly4-methyl-1-pentene, or a modified polyolefin obtained by treating the above-mentioned polyolefin with maleic anhydride. Among these, polypropylene resins have particularly poor compatibility with EVOH, and are important in that the effects of the present invention are particularly remarkable.

Polystyrene is a resin containing at least 25% by weight of a structural unit represented by the following general formula.

(Here, R is a hydrogen atom or a methyl group, Z is a) \rogen atom or a methyl group, and p is 0 or an integer of 1 to 3. ) Specifically, polyethylene, rubber-modified polystyrene, styrene-acrylonitrile copolymer, styrene-
Examples include homopolymers and copolymers of styrene and its derivatives, such as butadiene-acrylonitrile copolymers. Blends of these resins with styrene-conjugated diene block typical rubbers and hydrogenating agents thereof are also applicable.

Polyamides are produced by polycondensation reaction of ω-aminocarboxylic acid or polycondensation reaction of dibasic acid and diamine, and include 6-nylon, 6-6 nylon, 610-nylon,
Examples include 11-nylon, 12-nyloy, and copolymers thereof, and particularly preferred is a copolymer polyamide resin of ε-caprolactam and hexamethylene diammonium adipate.

Polyesters are those obtained by polymerizing saturated dibasic acids and glycols, such as polyethylene terephthalate obtained from ethylene glycol and terephthalic acid, phthalic acid, isophthalic acid, sebacic acid, adipic acid, azelaic acid, and glutaric acid. , a polyethylene terephthalate copolymer containing saturated dibasic acids such as succinic acid and oxalic acid as a copolymer component, and a copolymer component containing 1,4-cyclohexane dimethatol, diethylene glycol, propylene glycol, etc. as a diol component. Polyethylene terephthalate copolymer or polybutylene, or a blend thereof.

In the present invention, EVOH (B) is a saponified ethylene-vinyl acetate copolymer, and contains ethylene
60 mol%, preferably 25 to 50 mol%, and the degree of saponification of the vinyl acetate component is 90% or more, preferably 95% or more. If the ethylene content is less than 20 mol%, the melt moldability will be poor, while if it is 60 or more, the gas barrier properties will be insufficient. Furthermore, if the degree of saponification is less than 90%, gas barrier properties and thermal stability will deteriorate.

The EVOH may also contain other monomers such as propylene, butylene, unsaturated carboxylic acids or their esters ((meth)acrylic acid, (meth)acrylic esters (methyl, (ethyl), etc.), vinyl 7-rane compounds (vinyltrimethoxysilane, triethoxysilane, etc.), vinylpyrrolidone (N-
It is also possible to copolymerize plasticizers, heat stabilizers, ultraviolet absorbers, antioxidants, colorants, fillers, and other resins (such as polyamides, partially saponified ethylene-vinyl acetate copolymers). ) can also be freely blended. In addition, a suitable melt index (Ml') of EVOH used in the present invention (190°C, 2
(under 160g load) is 0.1 to 50g/10 minutes, optimally 0.5 to 20g/10 minutes.

In the present invention, as the adhesive resin (C), as long as it has strong adhesiveness to both (A) and (B), it is not limited to unsaturated carboxylic acid or The anhydride (maleic anhydride, etc.) can be used to make polyolefin resins (olefin polymers or copolymers) [polyethylene (low density polyethylene (LDPE), linear low density polyethylene (LLDPE), very low density polyethylene (SLDPE)]. l Ethylene-vinyl acetate copolymer, ethylene=(meth)acrylic acid copolymer, ethylene-
Those grafted onto (meth)acrylic acid ester (methyl ester, (ethyl ester) copolymer, etc.) are preferably used.

Silane-modified polyolefin resin used in the present invention (
D) is a polyolefin resin treated with a silane compound. For example, a silane compound is graft-polymerized onto a polyolefin resin using an electron beam or peroxide, or a comonomer (vinyl silane compound) is added to the polyolefin resin in the polymerization process. Examples include resins obtained by copolymerization. In addition, as a polyolefin resin,
Examples include the above-mentioned polyolefin (A),
In addition, styrene-monoolefin (ethylene, propylene, butylene, etc.) copolymers, styrene diolefin (
butadiene, isoprene, etc.) block copolymers or hydrogenated products thereof, diolefin resins (polybutadiene, polyisoprene, etc.) or hydrogenated products thereof are also exemplified. Among these, polyethylene resins, polypropylene resins, ethylene-propylene copolymers, and hydrogenated styrene-diolefin block copolymers are particularly preferred.

Further, as the silane compound (vinyl silane compound), compounds represented by the following (1), (II) and (II[) are suitable.

[However, here, n is 0 to 1, m is 0 to 2, R1 is a lower alkyl group, an allyl group, or a lower alkyl group having an allyl group, R2 is an alkoxyl group having 1 to 40 carbon atoms, and the alkoxyl group may have an oxygen-containing substituent. R3 is hydrogen or a methyl group, R4 is hydrogen or a lower alkyl group, and R5 is an alkylene group or 2I in which chain carbon atoms are bonded to each other by oxygen or nitrogen.
The organic residue of ilii, R8 is hydrogen, halogen, lower alkyl group R? is an alkoxy group or an acyloxyl group (herein, the alkoxyl group or acyloxyl group may have a substituent having oxygen or nitrogen), and R'' is hydrogen, halogen, lower alkyl group, allyl group, or allyl group. R8 is a lower alkyl group.] More specifically, R1 is a lower alkyl group having 1 to 5 carbon atoms, an allyl group having 6 to 18 carbon atoms, or an allyl group having 6 to 18 carbon atoms.
It represents a lower alkyl group having 1 to 5 carbon atoms and has 18 allyl groups, R4 represents a hydrogen atom or a lower alkyl group having 1 to 5 carbon atoms, and R6 represents an alkylene group having 1 to 5 carbon atoms or a chain carbon atom. 2 organic residues bonded to each other by oxygen or nitrogen; R8 is hydrogen, halogen, lower alkyl group having 1 to 5 carbon atoms, allyl group having 6 to 18 carbon atoms, or allyl group having 6 to 18 carbon atoms; carbon number 1~
5 represents a lower alkyl group, and R? represents an alkoxyl or acyloxyl group having 1 to 40 carbon atoms (the alkoxyl group or acyloxyl group may have a substituent having oxygen or nitrogen), and R8 is hydrogen, halogen, or a group having 1 to 5 carbon atoms. lower alkyl group, carbon number 6-18
represents an allyl group or a lower alkyl group having 1 to 5 carbon atoms having an allyl group having 6 to 18 carbon atoms, and R9 is an allyl group having 1 to 18 carbon atoms.
5 shows the lower alkyl group.

More specific chemical compounds include, for example, vinylmethoxysilane (vinyltrimethoxysilane, etc.), vinylethoxysilane (vinyltriethoxysilane), vinyltri(β-methoxy, ethoxy)silane, γ-methacryloxypropylmethoxysilane, etc. can give. Preferred are vinylmethoxysilane and vinylethoxysilane.

Silane-modified polyolefins also include polyolefin resins blended with silica that has been surface-treated with a silane coupling agent or the like.

The silicon (Si) content, the content of the above-mentioned adhesive resin (C), and the E V OH (B) content are important as they greatly affect the performance of the blend composition.

In the present invention, the silicon (Si) content in (D) is 0,0001 to 0.1% by weight based on the total weight of (A), (B), (C) and (D). The content is preferably 0.0005 to 0.05% by weight.

If the silicon content is less than 0.0001% by weight, the effects of the present invention cannot be sufficiently exhibited, and even if it exceeds 0.1% by weight, the effects of the present invention cannot be sufficiently exhibited.

In addition, the weight ratio of adhesive resin (C) to E V OH (B) must be 5/95≦(C)/(B)≦9515, and (C)/(B) must be 5/95. If it is less than that, new abnormalities such as generation of gels and lumps and increase in viscosity will occur, and the appearance of the molded product will be poor. On the other hand, when (C)/(B) exceeds 9515, the appearance becomes poor due to the generation of gels and spots.

Furthermore, in the present invention, silane-modified polyolefin (
D) is a thermoplastic resin (A) or EVOH (B)
Or some or all of the adhesive resin (C), or (A) and (B), (B) and (C), (C) and (A), (
When A), (B), and (C) are blended in advance and used in the recovery and reprocessing process, surprisingly, the film surface improvement effect during coextrusion is greatly improved, resulting in silane modification. Polyolefin (D) in advance (A)
, (B), and (C) and the Si content can be suppressed to about 115 to 1/1O lower than when used separately, so the generation of gel and bubbly is also at a lower level.

By the way, the silicon content can be determined by incinerating the composition and quantitatively analyzing it by atomic absorption spectrometry or fluorescent X-ray method after dissolving the composition as it is or by dissolving it with a strong acid.

Furthermore, E V OH (B) is 1 for the resin composition.
-60% by weight, more preferably 1-40% by weight. Mari (C>, (D)it, EV OH (B)it, respectively 0.1 to 10 times (weight), preferably 0.5 to
2 times (heavy ji) is blended.

Next, in the present invention, groups I, II and I of the periodic table are
It is more preferable to incorporate a salt or oxide (E) containing at least one element selected from Group II from the viewpoint of preventing gel formation. For example, many compounds are mentioned here, among others oxides such as calcium oxide, magnesium oxide, barium oxide, zinc oxide, metal (group ■, group ■ or group ■) salts of fatty acids, metal (I) salts of ethylenediaminetetraacetic acid. Group, ■ group, or ■ group) salts or hydrotalcites are effective. Furthermore, it has been found that among these compounds, salts containing metal elements of group I of the periodic table, such as magnesium, calcium, and zinc, tend to act particularly effectively. Examples of aliphatic metal salts of fatty acids (group I, ■■ or ■) include acetic acid, propionic acid, butyric acid, caproic acid,
Examples include lower aliphatic acids such as caprylic acid, and higher fatty acids such as lauric acid, stearic acid, and myristic acid.

Among these, metal salts of higher fatty acids having 8 to 22 carbon atoms, particularly calcium salts, magnesium salts, and zinc salts, are particularly suitable for the purpose of the present invention. Examples of metal (group I, group ■, or group ■) salts of ethylenediaminetetraacetic acid include disodium salt, trisodium salt, tetrasodium salt, dipotassium salt, tripotassium salt, tetrapotassium salt, disodium-magnesium salt, and disodium-magnesium salt. Calcium salts, disodium-magnesium salts, disodium-iron salts, disodium zinc salts, dipotassium-magnesium salts, and the like are suitable. In addition, as a hydrotalcite compound, especially M
XAIy(OH)tx-sy-tz(A)t'aoto
(M is Mgs Ca or Zu, A is CO, or HPO, x, y, z, a is a positive number) A hydrotalcite compound that is a double salt can be mentioned,
Among these, the following are particularly preferred.

Mg5A+z(ouLscos・4ut.

Mgs^1t(on)*. Co, 5H3OMgsAl
*(OH)+4COs・4H1OMg+. Alt(O)
l)t*(Co-)t・4H2OM'g*Alt(OH
)+5HPO4・4H1OCa, 1. (OH),,C
o, -4H1OZnsAls(OH)+*C05iHt
These hydrotalcite compounds not only improve the compatibility between EVOH and polyolefin, but also improve the hue of the molded product obtained.

The amount of additive (E) added in the total composition is 0.00
1 to 10% by weight, especially 0.01 to 5% by weight, are preferred. If it exceeds 10% by weight, physical properties other than compatibility are impaired and this is often undesirable. Additionally, the additive (E) is
One or more types may be used.

As for the blending method of resins (A), (B), (C
), (D) in a predetermined amount before use, and it is particularly preferable to use it by blending it with (D).

As a method for obtaining the composition of the present invention, thermoplastic resin (A
), EV OH (B), and a method of blending a modified polyolefin (D) into a composition containing an adhesive resin (C), in which one or more of (A), (B), or (C) is blended in advance. A method of blending and using (D), and further, a composition containing (A), (B), and (C), (A),
(D) in one or more of (B) or (C);
There are ways to blend things that are blended together.

Among them, (D) Ruai is a blend of (D) + (A) or a blend of (D) + (C) (A), (B), (C).
) is effective.

There are no particular restrictions on the blending method,
Examples include the triblend method and the brivelletization method using a twin-screw or twin-screw extruder. Among them, the brivelletization method using a single-screw extruder having a kneading section is effective.

In addition, when blending, it is necessary to avoid moisture absorption of raw materials, especially compositions containing EVOH.
It is preferable to dry the EVOH at ~140'C for 6 to 24 hours so that the moisture content in EVOH is 1% by weight or more, preferably 0.5% by weight or less before use.

As for (E), it can be added anywhere as in (D) above, but it is more suitable to blend it with (D).

The composition (F) of the present invention can also be used as a single layer,
It can also be used in a multi-layered manner including a (A) layer, a (B) layer, and a (C) layer. The layer structure is not particularly limited, but more preferably (A)/(F)/
(C) / (B) / (C) / (F) / (A), (
A) / (F) / (C) / CFS) / (C) / (
A), (F)/ (C)/ (B)/ (C)/ (A
), (F)/ (C)/ (B)/ (C)/ (F)
These layer structures are effectively used for sheets, films, bottles, cups, molded products, etc.

In particular, when the (F) layer is stretch-molded, such as 5PPP (vacuum-pressure solid-phase forming) in a sheet, stretch blow molding, etc., since (D) and (C) are blended, the (F) It is noteworthy that the transparency of the layer is greatly improved compared to systems in which (D) or/and (C) are not blended.

A more detailed explanation will be given in Examples below, but the present invention is not limited thereto in any way.

Example 1 In a four-type, seven-layer coextrusion facility, P P (A) (polypropylene), E VOH (1) (B) (ethylene content 32 mol%, saponification degree 99.5%), adhesive resin (
C) (maleic anhydride-modified PP) and for the recovery layer 80 parts by weight of PP, 1 part by weight of EVOHIO, 7 parts by weight of adhesive resin, and 0.1% by weight of vinyl trimethoxy in homopolypropylene under a dig silver oxide catalyst. Composition (F), in which parts of silane-modified PP3ffi obtained by melting silane reaction were pelletized using a single-screw extruder having a cross-wire section, was charged into each of four extruder popper units (A)/(F). ')/ (C)/ (B)/(C)/
A multilayer sheet having the (P)/(A) configuration was molded. The thickness of each layer at this time is (A) = 150μ, (F) = 30
0μ, (C) = 20μ, (B) = 60μ, total 1000
μ, and although there were many bumps, the appearance was good. Further, even when this sheet was folded, cut with scissors, or struck, no whitening due to delamination of the collected layer or peeling within the layer occurred. When the sheet was heated to 150° C. and thermoformed (SPPF solid phase stretch molding), a molded product with good transparency was obtained. This container was then filled with water and dropped onto a concrete floor from a height of 200 meters, but no rupture or localized whitening due to delamination was observed.

Examples 2 to 8 and Comparative Examples 1 to 7 A multilayer sheet was obtained under the same conditions as in Example 1 except as shown in Table 1, and the sheet was further thermoformed to obtain a molded product.
Margin below (note) PET: Polyethylene terephthalate PP: Polypropylene HIPS: Impact-resistant polystyrene EvOH (1): Ethylene content 32 mol%, saponification degree 9
9.6% EVOH EvoH (2): ethylene content 44 mol%, degree of saponification 9
9.4% EVOH A d (1): Maleic anhydride modified polypropylene A d (2): Maleic anhydride modified ethylene-vinyl acetate copolymer A d (3): Maleic anhydride modified ethylene-acrylic acid ethyl ester Copolymer 5i-PP Nidyran modified polypropylene 5i-PE Nidyran modified polyethylene 5t-3 EPS Nidyran modified styrene-ethylene-propylene block copolymer Hydrogenated product of styrene-isoprene block copolymer) Sr-5EBS Nidyran modified styrene-ethylene -Butylene block copolymer (hydrogenated product of ethylene-butadiene block copolymer) Sheet appearance (sloping): Excellent = No sagging on the film surface of the molded product.

Excellent = Midareho on the film surface of the molded product No need.

Good = Some sagging on the film surface of the molded product Yes, but it is a practical problem. none.

Defective = large sagging on the film surface of the molded product difficult to use in practice.

Sheet appearance (gels and lumps) excellent; no gels or lumps were observed on the film surface of the molded product.

Good = Gel/gel on the film surface of the molded product Although there are some problems, it is practical no problem.

Defective - There are many defects on the film surface of the molded product. gel bud or large Nagel Butsu is recognized It will be done.

F, Q51 According to the present invention, when collecting scraps of a multilayer structure containing EVOH, the film surface of the molded product that occurs during use,
Delamination inside the recovery layer or secondary processing of these (
It is possible to provide a resin composition that greatly improves the deterioration in transparency that occurs during (stretching, solid-state thermoforming).

Claims (7)

[Claims] (1) Thermoplastic resin (A), ethylene content 20-60
mol% of ethylene-vinyl alcohol copolymer (B),
An adhesive resin (C) having adhesive properties to both the resins (A) and (B) and a silane-modified polyolefin resin (D
), and the content of silicon (Si) in (D) is 0 with respect to the total amount of (A), (B), (C) and (D).
．． 0001 to 0.1% by weight of the resin composition. (2) The resin composition according to claim 1, wherein the thermoplastic resin (A) is a low water absorption thermoplastic resin. (3) The resin composition according to claim 1, wherein the thermoplastic resin (A) is at least one selected from polyolefin, polyester, polyamide, polystyrene, polycarbonate, and polyvinyl chloride. (4) The resin composition according to claim 1, wherein the adhesive resin (C) is a polyolefin resin grafted with an unsaturated carboxylic acid or its anhydride. (5) The silane-modified polyolefin resin is obtained by treating at least one selected from polyethylene resin, polypropylene resin, ethylene-propylene copolymer, and hydrogenated styrene-diolefin block copolymer with a silane compound. The resin composition according to claim 1, 2 or 3. (6) In the resin composition according to claim 1, group I of the periodic table,
The resin composition according to any one of claims 1 to 5, comprising a salt or oxide (E) containing at least one element selected from Group II and Group III. (7) The resin composition according to claim 6, wherein (E) is at least one selected from metal salts of ethylenediaminetetraacetic acid, hydrotalcite compounds, and metal salts of higher fatty acids having 8 to 22 carbon atoms.