JPH10231333A - Production of polyethylene oxide graft copolymer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a polyethylene oxide graft copolymer capable of extremely improving wettability with water while maintaining moldability and appearance of molding product which are essential properties of a polyolefin resin. SOLUTION: This method for producing a polyethylene oxide graft copolymer comprises compounding (a) 100 pts.wt. of a polyolefin resin in a molten state with (b) 0.01-10 pts.wt. of a radical initiator, (c) 0.1-30 pts.wt. of a compound containing a terminal alkyl group-containing polyethylene oxide chain of the formula -(CH2 CH2 O)n -R<1> (R<1> is a 1-25C alkyl group; (n) is an integer of 2-100) and a radically polymerizable unsaturated double bond. The polyolefin resin is preferably an ethylene-based polymer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a polyethylene oxide graft copolymer having significantly improved wettability to water while maintaining the moldability and appearance of a molded article which are inherent properties of a polyolefin resin. Yes, because of its excellent wettability, anti-fog properties,
It can be used in fields requiring antistatic properties and the like.

[0002]

2. Description of the Related Art Polyolefin resins have a poor affinity (hereinafter simply referred to as "wettability") with strongly polar substances due to their non-polar molecular structure, and they have antistatic properties and adhesive properties. Various properties such as paintability, printability, and drip-freeness (antifog properties as sheets and films) are remarkably inferior. As a method for solving these drawbacks, a method of introducing a hydrophilic functional group (hereinafter referred to as a hydrophilic group), for example, a method described in JP-A-54-16
No. 0449 discloses that a propylene-based polymer is an ester of polyhydric alcohol, acrylic acid or methacrylic acid,
Further, a method is disclosed in which a compound containing at least one hydroxyl group is melt-mixed in the presence of an organic peroxide. However, in such a method, the method disclosed in
By using polyethylene glycol methacrylate or acrylate having a terminal hydroxyl group as exemplified in JP-A-4-160449, a polyethylene oxide having a practically sufficient wettability on the surface of a molded article without impairing moldability and appearance of the molded article can be obtained. The polymer cannot be obtained.

On the other hand, Japanese Patent Application Laid-Open No. 6-256430 discloses that an olefin resin is modified by melt-kneading under reduced pressure using a hydroxyl group-containing α, β-unsaturated carboxylic acid ester and an aromatic vinyl compound to obtain a graft. A method for increasing the amount of polymerization is disclosed,
In the case of using a compound having a terminal polymerizable polyethylene oxide and a radical polymerizable unsaturated double bond as exemplified in JP-A-256430, the molded product surface is practically applied to the surface of the molded article regardless of the presence or absence of the reduced pressure condition even by the addition of styrene. It was difficult to obtain a polyethylene oxide copolymer having sufficient wettability.

[0004]

DISCLOSURE OF THE INVENTION The present invention provides a polyolefin resin having good moldability and high hydrophilicity without deteriorating the moldability and appearance of the molded product, and provides a practically sufficient wettability to the surface of the molded product. It is an object of the present invention to provide a method for producing a polyethylene oxide graft copolymer.

[0005]

Means for Solving the Problems The present inventors have conducted intensive studies to achieve these objects, and as a result, have found that the above objects can be achieved by melt-kneading a polyolefin resin using a specific compound. They have found that they can do this and have completed the present invention. That is, the method for producing the polyethylene oxide graft copolymer of the present invention comprises:
It is characterized by melt-kneading the following components (a) to (c). (A) 100 parts by weight of a polyolefin resin (b) 0.01 to 10 parts by weight of a radical initiator (c) A polyethylene oxide chain represented by the following formula [I] and having a terminal alkyl group and a radically polymerizable unsaturated double Compound having a bond 0.1 to 30 parts by weight — (CH ₂ CH ₂ O) _n —R ¹ [I] (wherein, R ¹ is an alkyl group having 1 to 25 carbon atoms, and n is 2 to 100)

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION

(1) Raw Materials (a) Polyolefin Resin [Component (a)] The polyolefin resin used in the method for producing a polyethylene oxide graft copolymer of the present invention has 2 carbon atoms.
And α-olefin homopolymers or copolymers containing these as main components. Examples of the α-olefin include ethylene, propylene, 1-butene, 1-hexene, 1-octene, 1-decene, 3-methyl-1-butene, 3-methyl-1-pentene, and 4-methyl-1-pentene. , 3-methyl-1-hexene and the like. These α-olefins may be used alone or in combination of two or more. Examples of the monomer copolymerizable with the α-olefin of the copolymer include conjugated dienes such as butadiene and polar monomers such as vinyl acetate, acrylic acid, acrylate, methacrylic acid, and methacrylic ester. Copolymers of α-olefins and these monomers may be used in combination of two or more. Of these, low-density polyethylene and polypropylene are preferably used as homopolymers of α-olefin, and copolymers containing α-olefin as a main component include ethylene and propylene.
-Butene, 1-hexene, a copolymer with 1-octene,
Alternatively, a copolymer of ethylene and vinyl acetate is preferred.
These polyolefin resins may be used alone,
Two or more kinds may be used in combination.

(B) Radical initiator [Component (b)] As the radical initiator used in the method for producing a polyethylene oxide graft copolymer of the present invention, t-butyl hydroperoxide, cumene hydroperoxide, 2,2 5
-Dimethylhexane-2,5-dihydroperoxide,
t-butyl peroxide benzoate, benzoyl peroxide, dicumyl peroxide, 1,3-bis (t-
Organic or inorganic peroxides such as butyl, peroxyisopropyl) benzene, dibutyl peroxide, methyl ethyl ketone peroxide, potassium peroxide, and hydrogen peroxide;
2,2-azobisisobutyronitrile, 2,2-azobis (isobutylamide) dihalide, 2,2-azobis [2-methyl-N- (2-hydroxyethylpropionamide)], azodi-t-butane and the like And a carbon radical generator such as dicumyl can also be used. Among these, it is preferable to use 1,3-bis (t-butylperoxyisopropyl) benzene. These radical initiators can be appropriately selected in relation to the ethylene oxide chain length n, the number of carbon atoms of the alkyl group or the reaction conditions of the compound represented by the formula [I], and two or more kinds may be used in combination. it can. These radical initiators can also be used by dissolving them in an organic solvent or the like. The amount of the radical initiator is 0.01 to 10 parts by weight, preferably 0.02 to 5 parts by weight, and particularly preferably 0.02 to 2 parts by weight, based on 100 parts by weight of the polyolefin resin. is there. If the amount is less than the above range, a sufficient graft amount cannot be obtained. If the amount exceeds the above range, the polyolefin resin is significantly deteriorated, and the moldability of the produced copolymer is reduced.

(C) Compound having a polyethylene oxide chain having a terminal alkyl group and a radically polymerizable unsaturated double bond [Component (c)] In the method for producing a polyethylene oxide graft copolymer of the present invention, component (c) The compound having a polyethylene oxide chain whose terminal is an alkyl group and a radically polymerizable unsaturated double bond is a compound represented by the above formula [I]. The radical polymerizable unsaturated double bond in the compound of component (c) and the terminal alkyl polyethylene oxide chain may be chemically bonded in any manner. Specific examples of the chemical bond include an ester bond, an ether bond, an amide bond, an imide bond, and a urethane bond. The compound of the above component (c) is preferably an esterified product of an α, β-unsaturated carboxylic acid such as acrylic acid, methacrylic acid, maleic acid, maleic anhydride and a terminal alkylated polyethylene oxide, a vinylbenzyl group and a terminal alkyl And the like.

The carbon number represented by R ¹ in the above formula [I] is 1 to 25, preferably 1 to 12, particularly preferably 1 to 1.
The alkyl group of 0 may include a branched or cyclic structure in addition to a linear aliphatic group, and may further include an unsaturated bond. For example, methyl group, ethyl group, propyl group, n-butyl group, iso-butyl group, t-butyl group,
Pentyl group, hexyl group, cyclohexyl group, heptyl group, octyl group, nonyl group, decyl group, undecyl group,
Dodecyl group, tridecyl group, tetradecyl group, pentadecyl group, hexadecyl group, heptadecyl group, octadecyl group, nonadecyl group, eicosyl group, heneicosyl group, doeicosyl group, trieicosyl group, tetraeicosyl group, pentaeicosyl group, etc. it can.
These groups can be used alone or in combination of two or more. The ethylene oxide chain length n in the formula [I] is preferably 5 to 20, particularly preferably 5 to 2.
It is an integer of 0. Specific examples of such a compound include a terminal methoxy group polyethylene oxide monomethacrylate, a terminal methoxy group polyethylene oxide monomaleate, a terminal t-butyl group polyethylene oxide monomethacrylate, and a terminal methoxy group polyethylene oxide monomethacrylate. Acrylic esters, terminal methoxy group polyethylene oxide p-vinylbenzyl ether and the like can be mentioned. In addition, the addition amount of the compound having a polyethylene oxide having a terminal alkyl group and a radically polymerizable unsaturated double bond represented by the formula [I] is as follows:
0.1 to 3 parts per 100 parts by weight of polyolefin resin
0 parts by weight, preferably 1 to 25 parts by weight, particularly preferably 5 to 20 parts by weight. When the amount of the compound of the component (c) is less than the above range, wettability becomes practically insufficient, and when the amount exceeds the above range, the original moldability and appearance of polyolefin are remarkably deteriorated.

(D) Aromatic vinyl compound [Component (d)] (arbitrary component) The use of an aromatic compound in the present invention is preferable because fish eyes in the case of forming a film can be further reduced. As the aromatic compound used as the component (d), for example, styrene, α-methylstyrene, α-methoxystyrene, methylstyrene,
Dimethylstyrene, 2,4,6-trimethylstyrene,
Chlorostyrene, dichlorostyrene, bromostyrene,
Examples thereof include nitrostyrene, chloromethylstyrene, cyanostyrene, t-butylstyrene, and vinylnaphthalene, among which styrene is preferred. These can be used alone or in combination of two or more. The amount of the aromatic vinyl compound to be added is generally arbitrary, but is preferably 0.1 to 30 parts by weight, preferably 0.5 to 30 parts by weight, per 100 parts by weight of the polyolefin resin.
It is preferably 20 parts by weight, particularly preferably 1 to 10 parts by weight. If the amount of the aromatic vinyl compound is less than the above range, fish eyes tend to increase during film formation. Further, when the amount exceeds the above range, wettability tends to decrease.

(E) Other optional components [Component (e)] The polyethylene oxide graft copolymer of the present invention comprises:
One or more kinds of polymers selected from those other than the above-mentioned polyolefin resins can be used as long as the effects of the present invention are not significantly impaired. In addition, well-known antioxidants, weathering improvers, nucleating agents, flame retardants, plasticizers, flow improvers, mold release agents, antifog agents, slip agents, antioxidants, which are used as additives for polyolefin resins Arbitrary components such as a blocking agent and a heat retaining agent can be used as additional components as long as the effects of the present invention are not significantly impaired. In addition, in order to improve rigidity, heat resistance, dimensional accuracy, etc., organic / inorganic fillers, reinforcing agents, particularly glass fibers, mica, talc, wollastonite, potassium titanate, calcium carbonate, silica, etc. may be added. it can. Furthermore,
In order to improve the practicality, various well-known coloring agents and their dispersants can be used within a range that does not significantly impair the effects of the present invention. These optional components can be added before or after melt-kneading for the graft reaction.

(2) Melt Kneading Melt Kneading Apparatus The melt kneading performed in the method for producing a polyethylene oxide graft copolymer of the present invention is performed by a device such as a kneader, a kneading extruder or a stirrer. Specifically, a horizontal twin-screw stirrer such as Labo Plast Mill, a single-screw or double-screw multi-screw kneader, a roll, a Banbury mixer, a horizontal twin-screw multi-disc device or a horizontal twin-screw surface renewal machine, or a double helical ribbon A vertical stirrer such as a stirrer can be used.

Melt Kneading Method As a method of melt kneading performed using the above-mentioned apparatus, a kneading method generally used for thermoplastic resins can be applied. For example, the powdery or granular components, if necessary, are uniformly mixed with the additives described in the section of the additional components by a Henschel mixer, a ribbon blender, a V-type blender, etc., and then melted by the above-described apparatus. It is a method of kneading. The order of addition of each component in the melt kneading may be a method of simultaneously kneading all the components or a method of melt kneading using a preliminarily blended blend. Further, a method in which each component is fed and melt-kneaded sequentially from the middle of the kneading extruder may be used. In that case, the polyolefin resin is generally added from a hopper of a kneading extruder, but a method of sequentially adding other components in the middle of the kneading extruder may be used.

These addition methods and order can be arbitrarily changed. In addition to the method of mixing and adding all other components, first, a mixture of an aromatic vinyl compound and a radical initiator is added. Examples of the method include a method of adding the compound represented by the formula [I], and a method of sequentially adding the compound in the reverse order. Further, a small amount of an organic solvent such as xylene can be added to improve the reaction efficiency and adjust the viscosity during kneading. Further, for the purpose of preventing deterioration due to oxygen at the time of melt-kneading, deaeration may be performed at a cylinder position of an arbitrary extruder, or kneading may be performed by adding nitrogen. The temperature of the melt-kneading can be any temperature as long as the polyolefin resin is in a molten state, but is preferably a temperature of 150 to 250 ° C. for prevention of deterioration and the like. Melt kneading time is generally 0.0
The range is 1 to 10 minutes, preferably 0.1 to 5 minutes.

(3) Molding Method The polyethylene oxide graft copolymer of the present invention obtained by the above production method can be molded by various molding methods. More specifically, molding methods commonly used for thermoplastic resins, namely, injection molding, hollow molding, sheet molding, thermoforming, rotational molding, lamination molding, press molding, inflation molding, T-die molding,
Various molding methods such as calender molding can be applied. Further, the film obtained by molding the polyethylene oxide graft copolymer obtained by the production method of the present invention is not limited to a single-layer film,
It may have a multilayer structure with this as a surface layer.

[0016]

The present invention will be described below more specifically with reference to examples and comparative examples. [I] Measuring method (1) Melt flow rate (MFR) Based on JIS-K7210, measurement was performed with a melt indexer manufactured by Toyo Seiki Co., Ltd. at a temperature of 190 ° C and a load of 21.2N. (2) Dynamic contact angle The polyethylene oxide graft copolymer was press-molded at 200 ° C. to obtain a film having a thickness of about 100 μm, and the film was punched into the shape shown in FIG. 1 to prepare a test piece. Using a surface tensiometer manufactured by Shimadzu Corporation, the test piece was measured by moving it forward and backward at a moving speed of 5 mm / min in distilled water as shown in FIG. (3) Appearance of Molded Product A film was molded using an inflation molding machine attached to Labo Plastmill manufactured by Toyo Seiki Seisakusho Co., Ltd. in which the cylinder temperature was set to 180 ° C., to obtain a film having a thickness of about 50 μm.
Then, the fish eye of this film was measured and evaluated according to the following criteria. Evaluation criteria ◎: 10 pieces / 1200 cm ² or less ○: 11-20 pieces / 1200 cm ² Δ: 21-50 pieces / 1200 cm ² ×: 51 pieces / 1200 cm ² or more

[II] Examples and Comparative Examples Examples 1 to 3 and Comparative Examples 1 to 4 After sufficiently mixing with a super mixer using the ingredients and the proportions shown in Tables 1 and 2 as raw materials, The mixture was cooled to 10 ° C. with a Labo Plast Mill manufactured by Toyo Seiki Seisaku-sho, Ltd., in which the cylinder temperature was set at 180 ° C.
The mixture was melt-kneaded at 0 rpm for 2 minutes, and pulverized after the completion of the melt-kneading to obtain a polyethylene oxide copolymer. The MFR, dynamic contact angle, and appearance of the molded product of this polyethylene oxide graft copolymer were measured, and the results are shown in Tables 1 and 2.

Comparative Example 5 Low density polyethylene alone shown in Table 2 was molded and evaluated in the same manner as in Example 1. Table 2 shows the results.

[0019]

[Table 1]

[0020]

[Table 2]

[0021]

The polyethylene oxide graft copolymer obtained by the process for producing a polyethylene oxide graft copolymer according to the present invention has a wettability to water while maintaining the moldability and the appearance of a molded article which are inherent characteristics of polyolefin resin. Has been greatly improved, and can provide not only sheets and films having excellent antifogging properties and drip-free properties, but also molded articles having excellent antistatic properties, and are industrially extremely useful materials.

[Brief description of the drawings]

FIG. 1 is a plan view showing the shape and dimensions of a test piece for measuring a dynamic contact angle.

FIG. 2 is an elevation view illustrating a measuring method for measuring a dynamic contact angle.

[Explanation of symbols]

 1 test piece 2 distilled water

Claims (4)

[Claims] 1. A method for producing a polyethylene oxide graft copolymer, comprising melt-kneading the following components (a) to (c). Component (a): 100 parts by weight of a polyolefin resin Component (b): 0.01 to 10 parts by weight of a radical initiator Component (c): a polyethylene oxide chain having a terminal alkyl group represented by the following formula [I]: Compound having a radical polymerizable unsaturated double bond 0.1 to 30 parts by weight — (CH ₂ CH ₂ O) _n —R ¹ [I] (wherein, R ¹ is an alkyl group having 1 to 25 carbon atoms, n Is an integer of 2 to 100) 2. A method for producing a polyethylene oxide graft copolymer, comprising melt-kneading the following components (a) to (d). Component (a): 100 parts by weight of a polyolefin resin Component (b): 0.01 to 10 parts by weight of a radical initiator Component (c): a polyethylene oxide chain having a terminal alkyl group represented by the following formula [I]: compounds 0.1 to 30 parts by weight having a radical polymerizable unsaturated double bond _{- (CH 2 CH 2 O)} n -R 1 [I] component (d): an aromatic vinyl compound 0.1 to 30 parts by weight ( In the formula, R ¹ is an alkyl group having 1 to 25 carbon atoms, and n is an integer of 2 to 100. 3. The method for producing a polyethylene oxide graft copolymer according to claim 1, wherein the polyolefin resin is an ethylene polymer. 4. The polyethylene oxide graft copolymer according to claim 1, wherein the component (c) is an ester compound of methacrylic acid or acrylic acid with polyethylene oxide having an alkyl group at one end. Production method.