JP3497103B2 - Ethylene-ethyl acrylate copolymer with high ethyl acrylate content and low melt mass flow rate, flame-retardant resin composition, flame-retardant resin molded product, and method for producing the copolymer - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a novel ethylene-ethyl acrylate copolymer having a high ethyl acrylate content (EA) and a low melt mass flow rate (MI), and the copolymer. TECHNICAL FIELD The present invention relates to a flame-retardant resin composition, a flame-retardant resin molded product obtained from the flame-retardant resin composition, and a method for producing the copolymer, and more specifically, filling properties such as magnesium hydroxide, heat resistance, and a machine. From ethylene-ethyl acrylate copolymer useful as a resin component for a flame-retardant resin composition excellent in dynamic strength, a flame-retardant resin composition containing the copolymer, and the flame-retardant resin composition The present invention relates to the obtained flame-retardant resin molded product and a method for producing the copolymer.

[0002]

2. Description of the Related Art Conventionally, ethylene-ethyl acrylate copolymer produced by a high pressure radical polymerization method has low temperature flexibility,
Not only does it have excellent physical properties in terms of impact strength, thermal stability, heat resistance, bending crack resistance, environmental stress crack resistance, impact resilience, etc., it is also flexible and has a high acceptability for fillers and inorganic flame retardants. Moreover, since it has excellent workability in that it can be easily processed by various molding machines for thermoplastic resins, for example, flexible hoses, grips, rings, films, sheets, wire coating materials, foot pumps, bumpers, It is used in various applications such as tires, waterstops, balls and hot melts.

However, when actually used for various purposes,
Ethyl acrylate content (wt%) of ethylene-ethyl acrylate copolymer (hereinafter simply referred to as "EA") and melt mass flow rate (g / 10 minutes) (hereinafter simply referred to as "MI") However, since the optimum range differs depending on the use and the required characteristics of the use, it is usually set within these required ranges. For example, in the application of hot melt, since fluidity and adhesiveness during processing are required, EA is 20 to 35% by weight,
MI of 300 to 600 g / 10 min is used, and in the application of flexible hoses, flexibility and mechanical strength are required. Therefore, EA is 15 to 20% by weight, M
Those having an I of 5 to 10 g / 10 minutes are used.

In recent years, research and development of non-halogen flame-retardant resin compositions have been actively carried out as a part of social efforts against environmental problems, and high-pressure process low-density polyethylene, linear low-density polyethylene, Chain-like ultra-low density polyethylene, ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer, etc. are used as the resin component, and magnesium hydroxide, aluminum hydroxide, calcium carbonate, etc. A flame-retardant resin composition highly filled with a flame retardant has been proposed. However, none of the flame-retardant resin compositions proposed so far has been sufficiently satisfactory in terms of performance, and each has some problems. For example, in the case of high-pressure method low-density polyethylene, linear low-density polyethylene, linear ultra-low-density polyethylene, etc., the filling properties of inorganic flame retardants such as magnesium hydroxide are insufficient, and therefore flame retardant In the case of ethylene-vinyl acetate copolymer, it is possible to fill magnesium hydroxide etc., but heat resistance is not sufficient. In addition, there is a possibility that acetic acid having a corrosive offensive odor may be generated when used at high temperature, and the mechanical strength was not sufficiently satisfactory.

On the other hand, the ethylene-ethyl acrylate copolymer has relatively few problems as compared with the above-mentioned resins, and is excellent in the filling property of magnesium hydroxide and the like, heat resistance, and mechanical strength. Therefore, at present, it is most often used as a resin component for such a flame-retardant resin composition. When using this ethylene-ethyl acrylate copolymer, EA is as large as possible, for example, 18 to 3 in order to improve the filling property of magnesium hydroxide and the like.
The amount used is 0% by weight, preferably 20 to 30% by weight, and the MI is as small as possible, for example, 1.5 to 2.5 g / 10, in order to improve the mechanical strength.
Minutes are used. However, if the MI is set to an extremely small value, for example, 1 g / 10 minutes or less while keeping the EA as large as possible, ethylene-ethyl acrylate copolymer having excellent mechanical properties and excellent filling property is obtained. Despite the expectation that a polymer will be obtained, the reason why the MI of 1.5 to 2.5 g / 10 min is used is that the conventional ethylene-ethyl acrylate copolymer is used. This is because it is difficult to produce such a high EA and low MI copolymer by the high pressure radical polymerization method. The reason for this difficulty is that the ethylene-ethyl acrylate copolymer produced from ethylene and ethyl acrylate by the high-pressure radical polymerization method generally increases MI as EA increases. For example, Japanese Patent Publication No. 6-47
No. 30 discloses that when a ethylene-ethyl acrylate copolymer is produced by a high-pressure radical polymerization method, it is produced under specific polymerization conditions to obtain the copolymer having excellent heat resistance (that is, high melting point). , A flame-retardant composition in which this and other resin components and an inorganic flame-retardant are blended is described. Looking at the properties of the ethylene-ethyl acrylate copolymer produced in the examples, EA is 10% by weight. %, MI is 0.5 g / 10
Although it was minutes, when EA was 25% by weight, MI showed an increase of 12 g / 10 minutes, which can be said to be exponential. Further, Japanese Patent Publication No. 6-37536 describes a method for producing an ethylene-ethyl acrylate copolymer by the high pressure radical polymerization method under the above-mentioned specific polymerization conditions, but here again, for example, EA is 20% by weight. %,
The copolymer having an MI of 1 g / 10 min or less is not described.

As described above, the EA is as high as 18 to 30% by weight, and the MI is low such that the following equation (2) MI ≦ 0.0494EA−0.141 (2) is satisfied. Ethylene-ethyl acrylate copolymers have been strongly desired in the field of flame-retardant resin compositions from the viewpoints of filling properties such as magnesium hydroxide and mechanical properties, but until now, such high EA and low There was no ethylene-ethyl acrylate copolymer of MI.

[0007]

In view of the above situation, an object of the present invention is to solve the problems of the conventional flame-retardant resin composition, so that the filling property of magnesium hydroxide or the like is improved. Sufficiently high EA, and sufficiently high mechanical properties of the obtained resin composition,
Provided are a novel ethylene-ethyl acrylate copolymer having a low MI and a method for producing the same, and further, a flame-retardant resin composition containing the novel ethylene-ethyl acrylate copolymer and the flame retardant. The object is to provide a molded product molded from the resin composition.

[0008]

As a result of intensive studies to solve the above-mentioned problems, the present inventors introduced ethylene and ethyl acrylate at a specific ratio from the inlet of a tubular reactor, and Compared to the radical polymerization method, higher E and lower temperature average reaction temperature conditions and by setting the maximum reaction temperature in the tubular reactor to a specific condition, high E
It has been found that a novel ethylene-ethyl acrylate copolymer having A and low MI can be produced. The present invention has been completed based on these findings.

That is, according to the present invention, the ethylene-acrylate content (% by weight) (EA) and the melt mass flow rate (g / 10 min) (MI) satisfy the formula (1): Method for producing ethyl acrylate copolymer
And a high pressure radical polymerization method using a tubular reactor.
To produce a copolymer of ethylene and ethyl acrylate
In this case, the following conditions (a) to (d) are satisfied: (a) Mol% of ethyl acrylate in ethylene (E)
Is in the range of 0.5 to 1.5 mol%, (b) the reactor inlet pressure (P) is 230 to 300 Mpa.
Is, (c) an average reaction temperature (Tave) is, 160 to 190 ° C.
Is, (d) the maximum reaction temperature (Tmax) is, 200 to 300 [° C.
The ethylene-acrylic acid is characterized in that
A method for producing an ethyl acetate copolymer is provided. 0.1 ≦ MI ≦ 0.0494EA-0.141
(1) (In the formula, EA represents the content (% by weight) of ethyl acrylate, and is in the range of 18.0 to 30.0% by weight, and M
I represents the melt mass flow rate (g / 10 minutes). )

Further, according to the present invention, the above formula (1)
Is in the range of 20.0 to 30.0% by weight, and the method for producing the ethylene-ethyl acrylate copolymer is provided.

[0011]

[0012]

[0013]

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below. 1. Ethylene-Ethyl Acrylate Copolymer The ethylene-ethyl acrylate copolymer of the present invention satisfies the following formula (1), but high-pressure radical polymerization using a tubular reactor set under specific conditions. Only legally can it be manufactured on a commercial scale. 0.1 ≦ MI ≦ 0.0494EA-0.141 (1) (In the formula, EA represents the ethyl acrylate content (wt%) in the range of 18.0 to 30.0 wt%, and MI is Melt mass flow rate (g / 10 minutes) is shown.) EA, which is the first requirement, is an inorganic flame retardant resin such as magnesium hydroxide in a flame-retardant resin composition using an ethylene-ethyl acrylate copolymer. It is an index linked to the filling property of a flame retardant into a resin component such as an ethylene-ethyl acrylate copolymer, and in the case of the present invention, the range of EA is set to 18.0.
30.0% by weight, preferably 20.0-30.0% by weight
By setting the above, it is possible to secure the same filling property as that of the flame-retardant resin composition using the ethylene-ethyl acrylate copolymer obtained from the conventional production method. EA is 1
If it is less than 8.0% by weight, the filling property of the inorganic flame retardant into the resin component becomes insufficient, and it becomes difficult to uniformly add the flame retardant in an amount required for flame retardancy. As a result, the flame-retardant resin composition may have a problem in quality control of mechanical strength such as tensile strength and impact strength. On the other hand, E
When A exceeds 30% by weight, the heat resistance of the ethylene-ethyl acrylate copolymer or the flame-retardant resin composition using the ethylene-ethyl acrylate copolymer decreases, which is not desirable.

The second requirement, MI, is an index linked to the mechanical strength of the ethylene-ethyl acrylate copolymer. The conventional one also depends on EA, but E
When A is 20 to 30% by weight, MI is 1 g / 1
Nothing was under 0 minutes. On the other hand, in the present invention, for example, when EA is 20.0% by weight, MI is
It is 0.85 g / 10 minutes or less, and as a result, it has very excellent mechanical strength as compared with the conventional one. Also, MI
Of less than 0.1 g / 10 minutes causes problems in productivity and extrusion processability, while MI is MI = 0.0494 EA.
When it is above the straight line represented by −0.141, mechanical properties such as tensile strength and impact strength are inferior to those of the present invention, which is not desirable.

The ethylene-ethyl acrylate copolymer of the present invention is a molded article not filled with a filler such as an inorganic flame retardant,
It can also be used in the field of sheets, films and the like, and in this case as well, it has more excellent mechanical properties as compared with the conventionally known ethylene-ethyl acrylate copolymer.

2. Polymerization Method The ethylene-ethyl acrylate copolymer of the present invention is produced by the high-pressure radical polymerization method using a tubular reactor set under specific conditions, as described above. Generally, the high-pressure radical polymerization method is a first method in which monomers ethylene and ethyl acrylate are pressure-fed to a tubular reactor by a high-pressure pump.
And a second step of copolymerizing in a tubular reactor under conditions of high pressure and high temperature using a radical generating catalyst such as an organic peroxide, and a reaction fluid containing the obtained copolymer. It comprises a third step of separating the copolymer and unreacted monomers by means of a high pressure separator.

The feature of the method for producing an ethylene-ethyl acrylate copolymer of the present invention resides in the second step. Therefore, the first step and the third step are not different from the conventional ones, and known conventional techniques can be used. Further, the unreacted monomer separated in the third step may be recycled.

That is, the polymerization method of the present invention comprises the following steps (a) to (e) when producing a copolymer of ethylene and ethyl acrylate by a high pressure radical polymerization method using a tubular reactor.
It is characterized by satisfying the requirement of (d). (A) Mol% of ethyl acrylate in ethylene (E)
Is in the range of 0.5 to 1.5 mol%. (B) The reactor inlet pressure (P) is 230 to 300 Mpa.
Is the range. (C) The average reaction temperature (Tave) is 160 to 190 ° C.
Is the range. (D) Maximum reaction temperature (Tmax) is 200 to 300 ° C.
Is the range.

The above requirements (a) to (d) will be described in detail below. First, the requirement (a) will be described.
To obtain the ethylene-ethyl acrylate copolymer of the present invention, mol% of ethyl acrylate in ethylene in a raw material fluid consisting of a mixed gas of ethylene and ethyl acrylate is used.
(E) needs to be in the range of 0.5 to 1.5 mol%. When this is less than 0.5 mol%, the EA of the ethylene-ethyl acrylate copolymer of the present invention is 18.
It becomes difficult to achieve 0% by weight or more, while if it exceeds 1.5 mol%, EA increases and 30.0% by weight.
Will be exceeded.

Next, the requirement (b) will be explained. In the first step, the raw material fluid is pressure-fed to the tubular reactor by the high-pressure pulsation pump, and in the second step, the high-temperature and high-pressure fluid is fed in the tubular reactor. Polymerization is carried out by a radical-generating catalyst such as an organic peroxide under the condition (1), and at that time, the inlet pressure (P) of the reactor is 230 to 300 MPa, preferably 250 to 280 MPa. This pressure is
Pressure 1 commonly used in high pressure radical polymerization processes to produce conventional ethylene-ethyl acrylate copolymers
Higher pressure than 50-230 Mpa. Further, the requirement (c) will be explained. Average reaction temperature (Tave)
As 160 to 190 ° C., preferably 165 to 18
5 ° C is adopted. This temperature is a little lower than the temperature adopted in the conventional high-pressure radical polymerization method (temperature exceeding 190 ° C.). Average reaction temperature (Tave)
If it is less than 160 ° C., an efficient polymerization reaction does not occur and the economical efficiency is lowered. On the other hand, when the temperature exceeds 190 ° C., the MI becomes high and it becomes difficult to obtain the ethylene-ethyl acrylate copolymer of the present invention. The average reaction temperature (Tave) in the present invention means the weighted average temperature of the temperature in each part from the inlet to the outlet of the tubular reactor.

Finally, the requirement (d) will be explained.
The raw material fluid pumped to the inlet of the tubular reactor is preheated in the preheating zone set on the inlet side of the tubular reactor, enters the polymerization zone, and is usually generated by cooling from the outside of the tubular reaction tube. The heat of polymerization is removed, and the maximum reaction temperature (Tm
ax) is reached, the polymerization reaction is controlled thereafter, and the tubular reaction tube goes out to the third step. The maximum reaction temperature (T
max) is 200 to 300 ° C., preferably 220 to 2
70 degreeC, More preferably, it is 230-270 degreeC. If the maximum reaction temperature (Tmax) is less than 200 ° C, the production efficiency will decrease, while if it exceeds 300 ° C, the MI of the obtained copolymer will be large, and the object of the present invention cannot be achieved. In the present invention, a tubular reactor having a length-to-diameter ratio of 4000: 1 to 80000: 1 can be favorably used.

In the polymerization method of the present invention, when the raw material monomer consisting of ethylene and ethyl acrylate is copolymerized,
A radical generating catalyst or a chain transfer agent is used. As the radical generating catalyst, a conventional catalyst such as an organic peroxide, an azo compound or oxygen is used. As the organic peroxide, di-t-butyl peroxide, t-butyl peroxybenzoate, dodecanol peroxide, lauryl peroxide, diacetyl peroxide, dipropyl peroxide, t-butyl peroxyacetate, t
-Butyl peroxyisobutyrate, dicumyl peroxide, t-butyl peroxy vivalate, di (t-butyl peroxy) adipate, t-butyl peroxy laurate, t-butyl peroxy-2-ethylhexano Examples thereof include ate, and examples of the azo compound include azobisisobutyronitrile. The amount of the radical generating catalyst used is usually 1 to 5 with respect to the raw material fluid composed of ethylene and ethyl acrylate, which are monomers to be supplied to the reactor.
It is 0 ppm by weight, preferably 2 to 30 ppm by weight.

On the other hand, as the chain transfer agent, a conventional chain transfer agent, for example, hydrogen; saturated aliphatic hydrocarbon having 1 to 20 or more carbon atoms such as propylene and butene-1;
Saturated aliphatic alcohols having 1 to 20 or more carbon atoms such as methanol, ethanol, propanol and isopropanol; Saturated aliphatic carbonyl compounds having 1 to 20 or more carbon atoms such as carbon dioxide, ketones and aldehydes; Aromatic compounds such as toluene, ethylbenzene and xylene are used. At that time, specific examples of the ketones include acetone, diethyl ketone, diamyl ketone, diisobutyl ketone, methyl ethyl ketone, methyl isopropyl ketone, ethyl butyl ketone, ethyl propyl ketone, diisoamyl ketone, and the like.
Specific examples of the aldehydes include formaldehyde, acetaldehyde, n-butyraldehyde, isobutyraldehyde, n-valeraldehyde, isovaleraldehyde, n-caproaldehyde, n-caprylaldehyde and the like. The amount of the chain transfer agent used is usually 0.2 to 10 mol%, preferably 0.5 to 5 mol%, based on the raw material fluid consisting of ethylene and ethyl acrylate, which are monomers to be supplied to the reactor. .

3. Resin composition The high EA and low MI novel ethylene-ethyl acrylate copolymer of the present invention is usually used alone as a resin component for a flame-retardant resin composition or a material for a molded article. Other resin components, such as high-pressure low-density polyethylene, linear low-density polyethylene, within a range that does not impair the physical properties,
Linear ultra-low density polyethylene, high density polyethylene, ethylene-vinyl acetate copolymer, conventional ethylene-
You may mix and use it, such as ethyl acrylate. Also,
At that time, general additives such as antioxidants, antifogging agents, antistatic agents, crosslinking agents, antiblocking agents, slip agents, colorants, antitree agents, crystal nucleating agents, stabilizers, and UV absorption. An agent, a light stabilizer, a processability improver, a dispersant, a copper damage inhibitor, a neutralizing agent, a foaming agent, an antifoaming agent, a crosslinking aid and the like may be added.

A preferred embodiment of the resin composition of the present invention is a flame-retardant resin composition obtained by blending a flame retardant with the above-mentioned high EA and low MI ethylene-ethyl acrylate copolymer. The flame retardant used in the flame retardant resin composition of the present invention is usually an organic halogen flame retardant, an organic phosphorus flame retardant, an inorganic flame retardant, or the like. At that time, as the organic halogen-based flame retardant, hexabromobenzene, decabromodiphenyl oxide, polydibromophenylene oxide, bis (tribromophenoxy) ethane, ethylene bis (pentabromobenzene), ethylene bis (dibromonorbornanedicarboximide) , Ethylenebis (tetrabromophthalimide), dibromoethyldibromocyclohexane, dibromoneopentyl glycol, tribromophenol, tribromophenol allyl ether, tetrabromobisphenol A derivative, tetrabromobisphenol S, tetradecabromodiphenoxybenzene, tris (2 , 3-Dibromopropyl-1) isocyanurate, 2,2-bis (4-hydroxy-3,5-dibromophenyl) propane, 2,2-bis (4- Mud ethoxy-3,5-dibromophenyl) propane,
Pentabromophenol, pentabromotoluene, pentabromodiphenyl oxide, hexabromocyclododecane, hexabromodiphenyl ether, octabromophenol ether, octabromophenyl ether,
Octabromodiphenyl oxide, dibromoneopentyl glycol tetracarbonate, bis (tribromophenyl) fumaramide, N-methylhexabromophenylamine, brominated epoxy resin, chlorinated paraffin, chlorinated polyolefin, chlorinated polyethylene, perchlorocyclopentadecane Etc. are illustrated.

Further, as the organic phosphorus flame retardant, tris (chloroethyl) phosphate, tris (monochloropropyl) phosphate, tris (dichloropropyl) phosphate, triallyl phosphate, tris (3-hydroxypropyl) phosphine oxide, tris (tri) Bromophenyl) phosphate, tetrakis (2-chloroethyl) ethylenediphosphate, glycidyl-α-
Methyl-β-di (butoxy) phosphenylpropionate, dibutylhydroxymethylphosphonate, di (butoxy) phosphenylpropylamide, dimethylmethylphosphonate, ethylenebis (tris (2-cyanoethyl)) phosphonium bromide, Examples thereof include amine phosphates such as ammonium polyphosphate and ethylenediamine phosphate, and amine phosphates.

Further, as an inorganic flame retardant, hydrotalcite, hydromagnesite, antimony trioxide, aluminum hydroxide, magnesium hydroxide, potassium hydroxide, calcium hydroxide, calcium phosphate, zircon oxide, titanium oxide, zinc oxide. , Magnesium oxide,
Magnesium carbonate, calcium carbonate, barium sulfate, barium borate, barium metaborate, zinc borate, zinc metaborate, anhydrous alumina, molybdenum disulfide, clay,
Red phosphorus, diatomaceous earth, kaolinite, montmorillonite, talc, silica, white carbon, zeolite,
Examples include asbestos and lithopone. When these inorganic flame retardants are used, the average particle size thereof is preferably 40 μm or less, more preferably 0.1 to 20 μm, from the viewpoint of dispersibility in the resin and uniform flame retarding effect. Further, the surface of the flame retardant is treated with a fatty acid such as stearic acid, oleic acid or parimitic acid or a metal salt thereof; paraffin, wax, or modified products thereof; organic silane, organic borane,
Alternatively, it is preferable to perform surface treatment with an organic titanate or the like. Needless to say, the organic halogen-based flame retardant, the organic phosphorus-based flame retardant, and the inorganic-based flame retardant may be used alone or in combination.

4. Molded Product As described above, the resin composition or the flame-retardant resin composition of the present invention comprises a resin component composed of an ethylene-ethyl acrylate copolymer having a high EA and a low MI, and an appropriate amount of various kinds. It is prepared by blending additives, resin auxiliary materials, crosslinking agents, flame retardants and the like. Mixing and preparing the resin composition,
V blender, tumbler blender, ribbon blender, rotary blade or fixed blade blender, Henschel mixer, etc., and the resin composition is in the form of a dry blend or a soaking product. As another mixing / preparing method, the copolymer and various additives, resin auxiliary materials, cross-linking agents, flame retardants and the like as they are, or in the form of the above dry blend or soaking material, There is a method of charging to a Banbury mixer, a Buscon kneader, a mixing roll, an intensive mixer, a single-screw extruder, a twin-screw extruder, a multi-screw extruder, a static mixer, and the like, and heating and melting and kneading, but either method may be used. . The heat-melted and kneaded product can be supplied to a molding machine as it is or after being made into pellets or powders to be a molded product. The mixing order of the above-mentioned components may be arbitrary, and a small amount of components such as an antioxidant, a cross-linking agent and an antistatic agent may be prepared in advance by preparing a high-concentration masterbatch with the copolymer or other resin of the present invention, This may be blended with the copolymer of the present invention and other components and mixed and prepared by dry blending or heat-melt kneading.

The ethylene-ethyl acrylate copolymer of the present invention is excellent in the filling property with respect to additives such as a flame retardant and the mechanical strength, and therefore, by utilizing its characteristics, flexible hoses, grips, rings, films, Seats, wire coatings, foot pumps, bumpers, tires, waterstops, balls, pipes, back-in boxes, squeeze boxes, standing punches, sandals, shoe soles, gaskets, rolls, packing, building materials, vehicle parts, electrical parts, Used as linings, roofing, tiles, sports equipment, aerospace parts, carpet backing materials, etc.

[0031]

The present invention will be described in more detail below with reference to examples and comparative examples, but these are merely examples, and the present invention is not limited to these examples. In addition, the measurement of the physical-property value in this invention was based on the following method.

Evaluation Method (1) Melt Mass Flow Rate (MI) The melt mass flow rate (MI) is JIS K721.
Test temperature 190 ° C., load 2.
It is a value measured at 16 kg.

(2) Ethyl acrylate content (EA) Ethyl acrylate content (EA) is the infrared absorption spectrum
860 cm by tor ^-1From the absorbance of
EA concentration is determined by the sound spectrum and a standard sample is used
It is the value calculated from the calibration curve that measured the above absorbance.
It

(3) Tensile Strength and Elongation The tensile strength of the sheet is a value measured by a method according to JIS K6760 at a sheet thickness of 1 mm, a JIS-3 dumbbell and a tensile speed of 200 mm / min.

(4) Oxygen index The oxygen index is determined by the method based on JIS K7201.
It is a value measured at a sheet thickness of 3 mm.

Example 1 The mol% (E) of ethyl acrylate in ethylene was 0.7.
A raw material fluid of 8 mol% was injected together with a radical generation catalyst of 4 ppm by weight from the inlet of the tubular reactor by a high pressure pulsation pump in a reactor inlet pressure (P) in a pulsating pressure range of 250 to 270 MPa. Average reaction temperature (Tave)
Is 170.2 ° C and the maximum reaction temperature (Tmax) is 27
It was 5 ° C. The obtained copolymer and unreacted monomer were taken out to a separation container through a control valve, and the copolymer was separated to obtain an ethylene-ethyl acrylate copolymer of the present invention. The physical properties of the obtained copolymer were measured and are shown in Table 1.
EA is 23.2% by weight and MI is 0.
Formula (1), which is 7 g / 10 min and is a requirement of the present invention:
0.1 ≦ MI ≦ 0.0494EA-0.141 was satisfied, and the filling properties and mechanical properties were well balanced.

[0037]

[Table 1]

Examples 2 to 4 Examples 2 to 4 are the same as Example 1 except that the mol% (E) of ethyl acrylate in ethylene and the average reaction temperature (Tav
e) and the maximum reaction temperature (Tmax) are shown in Table 1 respectively.
The same procedure as in Example 1 was carried out except that the conditions shown in Table 1 were used to obtain the ethylene-ethyl acrylate copolymer of the present invention. The results are shown in Table 1, and from Example 2 in which the mol% (E) of ethyl acrylate was increased, a copolymer having a higher EA was obtained, and in Example in which the mol% (E) was decreased. From Example 3, a copolymer having a lower EA than that of Example 1 was obtained, but the formula (1) which is a requirement of the present invention: 0.1 ≦ MI ≦
It was a low MI copolymer satisfying 0.0494EA-0.141. From Example 4 in which the average reaction temperature (Tava) and the maximum reaction temperature (Tmax) were lowered, the copolymer of the present invention having a high EA and a low MI was obtained.

Comparative Examples 1-5 Under the conditions shown in Table 1, ethylene-
An ethyl acrylate copolymer was prepared and their EA and MI were measured. In Comparative Example 1, the average reaction temperature (Tav
e) exceeding the range of the present invention, Comparative Example 2 having a maximum reaction temperature (Tmax) exceeding the range of the present invention,
In Comparative Example 3, the reactor inlet pressure (P) was lowered below the range of the present invention, in Comparative Example 4, the mol% (E) of ethyl acrylate in ethylene was increased, and in Comparative Example 5, Although the mol% (E) is lowered, M of the obtained copolymer is
In Comparative Examples 1 to 3, I is a formula (1) which is a requirement of the present invention: 0.1 ≦ MI ≦ 0.0494EA-0.141.
The condition was not satisfied and was larger than this. Further, the above mol% (E) was out of the range of the present invention (Comparative Example 4,
From 5), the EA of the obtained copolymer is the EA of the present invention.
Requirements for: Not satisfying the range of 18.0 to 30.0% by weight.

Example 5 In Example 5, 98 parts by weight of the ethylene-ethyl acrylate copolymer prepared in Example 1 was added to an ethylene-1-octene copolymer prepared with a metallocene catalyst (density: 0.900 g).
/ Cm ³ , MI: 0.8 g / 10 minutes, 5 parts by weight of a modified product obtained by adding 0.5% by weight of maleic anhydride of "Affinity" manufactured by Dow Chemical Co., Ltd., and 120 parts by weight of magnesium hydroxide. This mixture was kneaded with a Banbury mixer at 106 ° C. for 10 minutes to obtain a flame-retardant resin composition. Next, this flame-retardant resin composition is made into pellets, and the pellets are used to make 150
A sheet was obtained by molding for 3 minutes at a temperature of 100 kg / cm ² . For evaluation, dumbbell test pieces were prepared from this sheet, and the tensile strength, elongation and oxygen index were measured. This flame-retardant resin composition shows an oxygen index of 31, a tensile strength of 78 kg / cm ² and an elongation of 655%,
It was found to have excellent mechanical strength.

Comparative Example 6 The EA prepared in Comparative Example 2 was 23.4% by weight and the MI was 1.5.
A flame-retardant resin composition was obtained in the same manner as in Example 5 except that an ethylene-ethyl acrylate copolymer having a g / 10 min was used. When this flame-retardant resin composition was evaluated in the same manner as in Example 5, the oxygen index was 31, and the flame retardancy was the same, but the tensile strength was 75 kg / cm ² and the elongation was 6
The mechanical property was 25%, which was inferior to that of Example 5.

Example 6 98.22 parts by weight of the ethylene-ethyl acrylate copolymer prepared in Example 1 was mixed with an antioxidant (Irganox 10).
10) 0.20 parts by weight, light stabilizer (Chimassor)
b944LD) 0.30 parts by weight, slip agent (Diam
id200D) 0.15 parts by weight, antifogging agent (glycerin fatty acid ester) 0.12 parts by weight, and neutralizing agent (zinc stearate) 0.01 parts by weight are mixed, and ethylene is obtained by kneading at 150 ° C for 10 minutes. -An ethyl acrylate copolymer resin composition was obtained. Next, this resin composition was used for the middle layer and for the outer layer and the inner layer, using a metallocene catalyst, the density was 0.902 g / cm ³ , and the MI was 1.0 g.
/ 10 min of a linear ethylene-1-octene copolymer, various other additives are blended in the same manner as the ethylene-ethyl acrylate copolymer to obtain a resin composition, which is then subjected to an inflation method. As a result, a three-layer agricultural film having a middle layer of 50 μm and outer and inner layers of 25 μm was produced.
The obtained agricultural film had good transparency by visual evaluation and good tensile strength.

[0043]

INDUSTRIAL APPLICABILITY The novel high EA and low MI ethylene-ethyl acrylate copolymer obtained by the present invention is excellent in the filling property of a flame retardant such as magnesium hydroxide, and also excellent in mechanical strength. Therefore, by utilizing its characteristics, various fillers can be highly filled while maintaining mechanical strength, and for example, it can be suitably used for various molded products such as films and electric wire coating materials having a high degree of flame retardancy.

─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-5-140374 (JP, A) JP-A-4-23842 (JP, A) JP-A-3-263413 (JP, A) JP-A-5- 202131 (JP, A) (58) Fields surveyed (Int.Cl. ⁷ , DB name) C08F 6/00-246/00 C08F 2/00-2/60 C08L 1/00-101/14

Claims (2)

(57) [Claims] 1. An ethyl acrylate content (% by weight) (E
A) and melt mass flow rate (g / 10 minutes) (MI)
Ethylene-acrylic acid satisfying the formula (1)
A method for producing an ethyl copolymer, which comprises the following conditions (a) to (d) when producing a copolymer of ethylene and ethyl acrylate by a high pressure radical polymerization method using a tubular reactor: (A) Mol% of ethyl acrylate in ethylene (E)
Is in the range of 0.5 to 1.5 mol%, (b) the reactor inlet pressure (P) is 230 to 300 Mpa.
(C) The average reaction temperature (Tave) is 160 to 190 ° C.
(D) The maximum reaction temperature (Tmax) is 200 to 300 ° C.
The method for producing an ethylene-ethyl acrylate copolymer, characterized in that 0.1 ≦ MI ≦ 0.0494EA-0.141
(1) (In the formula, EA is the ethyl acrylate content (% by weight)
, In the range of 18.0 to 30.0% by weight, and M
I indicates the melt mass flow rate (g / 10 minutes)
You ) 2. Ethyl acrylate content (% by weight) (E
A) is an ethylene according to claim 1, characterized in that in the range of 20.0 to 30.0 wt% - method for producing ethyl acrylate copolymer.