JP6047953B2 - Olefinic resin processability modifier and method for producing the same - Google Patents

Description

  The present invention relates to a processability modifier that is mixed to improve processability in a polyolefin extrusion process, and a method for producing the same.

  In general, high-pressure low-density polyethylene produced by the high-pressure radical method exhibits excellent film-forming properties during extrusion laminating and is suitable for use in extrusion laminating to various resin films, paper, base films such as aluminum foil Has been. In recent years, in fields where impact strength and puncture strength are required or in fields where heat resistance is required, high-pressure low-density polyethylene lacks performance, and linear low-density polyethylene and high-density polyethylene have come to be used. Is coming. However, since both linear low density polyethylene and high density polyethylene are inferior in extrusion laminate moldability, it is difficult to use them alone. Therefore, processability modifiers such as high pressure method low density polyethylene are mixed and used. It has been. As the processability modifier used for the polyolefin resin, high-pressure low-density polyethylene having high elasticity is often used. In order to make use of the properties of linear low density polyethylene and high density polyethylene, such processability modifiers are required to be able to improve extrusion laminate formability with as little mixing as possible. Since the higher the elasticity, the better the extrusion laminate formability can be improved with a small amount of mixing, there is a need for a workability modifier that is more effective than conventional high-pressure low-density polyethylene.

  As a method for increasing the elasticity of a polyolefin resin, a method of irradiating an existing polyolefin resin with an electron beam or radiation as a post-treatment is known (for example, see Patent Documents 1 and 2). However, the method of irradiating with an electron beam or radiation requires a dedicated device, and has a drawback of increasing the cost for processing a large amount of resin. In addition, a method is known in which an existing polyolefin resin and a radical generator such as an organic oxide are cross-linked by melt mixing to increase elasticity (see, for example, Patent Document 3). According to this method, although it can be processed with a normal extruder, the obtained modifier has insufficient stretchability and is inferior in high-speed processability when mixed with linear low-density polyethylene or high-density polyethylene. There was a problem.

  As described above, in the conventional method, it is difficult to obtain a workability improving material having a high workability improving effect without impairing stretchability without using new equipment.

JP-A-9-31256 JP 2000-159947 A Japanese Patent No. 3044256

  The present invention has been made in view of the situation as described above, and is an olefin resin that can be greatly improved in workability without impairing stretchability by using high-pressure low-density polyethylene without using new equipment. A workability modifier is proposed.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that a modifier using a specific high-pressure method low-density polyethylene can greatly improve workability without impairing stretchability. It came to be completed.

That is, the present invention relates to an olefin-based resin processability modifier that is made of high-pressure low-density polyethylene and satisfies the following (A) to (B).
(A) The melt tension at 260 ° C. measured with a capillary viscometer is 145 mN or more. (B) The melt resin can be stretched at a stretch ratio of 4.7 or more under the conditions of measuring the melt tension with a capillary viscometer at 260 ° C. The present invention also relates to a process for producing a workability modifier, characterized by melt-kneading high-pressure low-density polyethylene under conditions that satisfy (C) to (E).
(C) Kneading temperature is 130 ° C. or more and 220 ° C. or less (D) Oxygen concentration is 0.1% or more and 21% or less (E) The filling rate of the molten resin in the kneading chamber is 40% or more and 90% or less. This will be described in detail.

  The processability improving material of the present invention is made of high-pressure low-density polyethylene.

  There is no particular restriction on the molecular weight distribution of the high-pressure low-density polyethylene used as a material for the processability modifier of the present invention, but the weight average molecular weight Mw and number are high because the original elasticity is high and the processability improvement effect is good. The average molecular weight Mn ratio Mw / Mn is preferably 6 or more, and more preferably 8 or more.

  Although there is no restriction | limiting in particular about MFR of the high pressure method low density polyethylene used as a material of the workability modifier of this invention, From the original elasticity being high and workability improvement effect becoming favorable, 1 g / 10min or more 10g / It is preferably 10 minutes or less, more preferably 1 g / 10 minutes or more and 5 g / 10 minutes or less.

The processability modifier of the present invention is equipped with a capillary viscometer with a barrel diameter of 9.55 mm and a die having a length of 8 mm, a diameter of 2.095 mm, and an inflow angle of 90 °, and the temperature is set to 260 ° C. The value of melt tension (hereinafter referred to as MS ₂₆₀ ) measured at a piston lowering speed of 10 mm / min and a draw ratio of 4.7 is 145 mN or more, preferably 150 mN or more, more preferably 160 mN or more. When the melt tension is lower than 145 mN, the elasticity of the modifier is low and the effect of improving workability is lowered, which is not preferable.

  The workability modifier of the present invention has a draw ratio of 4.7 or more when the melt tension is measured with a capillary viscometer at 260 ° C. A draw ratio of less than 4.7 is not preferable because high-speed formation is insufficient when mixed with an olefin resin such as linear low-density polyethylene or high-density polyethylene as a processability modifier.

In the present invention, when the melt tension MS ₂₆₀ is measured, if it can be stretched at a stretch ratio of 4.7, it is judged that it has good performance as a workability modifier, and the stretch at a stretch ratio of 4.7 is determined. When it was not possible, it was judged that high-speed formability was inferior as a workability modifier.

  When the ratio of before and after melt kneading of MS at 260 ° C. measured by a capillary viscometer is 1.8 or more, the workability modifying material of the present invention has high elasticity and high processing efficiency. Since a property modifier is obtained, it is preferable.

  In the processability modifier of the present invention, the ratio Mw / Mn of the weight average molecular weight Mw and the number average molecular weight Mn is preferably 6 or more because the molecular weight distribution is wide and the processability improving effect is good. More preferably, Mn is 8 or more.

  The workability modifier of the present invention uses high pressure method low density polyethylene. Elasticity can be increased by melt-kneading high-pressure low-density polyethylene. As a method of melt kneading, there are a method in which processing is performed continuously and a method in which processing is performed in a batch manner. Examples of the apparatus include various kneaders such as a banbury mixer, a roll mixer, a kneader, a high-speed rotary mixer, and an extruder in addition to a single-screw extruder and a twin-screw extruder.

  The apparatus for producing a workability modifier according to the present invention is preferably a twin screw extruder or a Banbury mixer because the kneading temperature and oxygen concentration can be easily adjusted. In addition, after melt-kneading with kneading machines, such as a Banbury mixer, it can shape | mold into a pellet form using a single screw extruder or a twin screw extruder.

  The melt kneading temperature for producing the workability modifier of the present invention is 130 ° C. or higher and 220 ° C. or lower, more preferably 140 ° C. or higher and 210 ° C. or lower, and further preferably 145 ° C. or higher and 200 ° C. or lower. Not only can the elasticity and stretchability of the material be compatible, it is preferable from the standpoints of the load on the kneader during melt kneading and productivity.

  The oxygen concentration at the time of melt-kneading for producing the workability modifier of the present invention is preferably 0.1% or more and 21% or less because both the elasticity and stretchability of the modifier can be achieved.

  The filling rate of the resin in the kneading chamber at the time of melt kneading for producing the workability modifier of the present invention is preferably 40% or more and 90% or less, more preferably 45% or more and 90% or less. Here, the resin filling rate in the kneading chamber is the ratio of the molten resin in the space between the extruder barrel and the screw in the case of an extruder, and the space between the mixing chamber and the rotor in the case of a Banbury mixer. It refers to the proportion of molten resin in the interior. It is preferable for the filling rate to be in this range since both elasticity and stretchability can be achieved.

  The olefinic resin processability modifier of the present invention exhibits excellent processability modification effects when mixed with olefinic resins such as linear low-density polyethylene and high-density polyethylene, extrusion laminate molding, inflation film molding It is suitably used for extrusion molding such as cast film molding. Among them, it is preferable to use it for extrusion laminate molding in which high elasticity is required for the workability modifier.

  The olefinic resin processability modifier of the present invention includes olefinic resins such as linear low density polyethylene and high density polyethylene, and dry blends that mix pellets, as well as Banbury mixers, roll mixers, kneaders, and high-speed rotations. Mixing can be carried out using a known method such as mixing and kneading using various kneaders such as a mixer and an extruder, preferably a single or twin screw extruder, and it can be used for various extrusion molding.

  By using the olefin-based resin processability modifier of the present invention, it becomes possible to improve the extrusion processability with a smaller amount of mixing than before. Thereby, the characteristics of the mixture can be reflected by the product.

  Moreover, the olefin resin processability modifier of the present invention can be produced using high-pressure low-density polyethylene without using new equipment and without sacrificing hygiene.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited to these Examples.

The evaluation methods for physical properties and processability are shown below.
(1) Melt tension of the reformer In a temperature-controlled room set at 23 ° C, the temperature is set at 260 ° C, and the barrel diameter is 9 with a die having a length of 8 mm, a diameter of 2.095 mm, and an inflow angle of 90 °. A .55 mm capillary viscometer (Toyo Seiki Seisakusho, trade name: Capillograph) is filled with 18 g of the reforming material, the piston lowering speed is set to 10 mm / min, the stretch ratio is set to 4.7, and the load necessary for take-up ( mN) was measured as melt tension (MS ₂₆₀ ).
(2) Melt tension of the mixture of the modifying material and the linear low-density polyethylene The modifying material and the linear low-density polyethylene (made by Tosoh Corporation) having a melt mass flow rate of 20 g / 10 min and a density of 936 kg / m ³ Nipolon-LM70K (hereinafter referred to as LL-A) is dry blended at a weight ratio of 20/80, and a set temperature of 160 ° C. using a single screw extruder (manufactured by Placo) having a 50 mmφ screw and a strand die. Then, it was extruded into a strand shape at a discharge amount of 25 kg / hour, and formed into a pellet using a strand cutter (manufactured by Seiwa Iron Works Co., Ltd.). A capillary viscometer (Toyo Seiki Seisakusho Co., Ltd.) having a barrel diameter of 9.55 mm, fitted with a die having a length of 8 mm, a diameter of 2.095 mm, and an inflow angle of 90 ° in a thermostatic chamber set at 23 ° C. (Product name: Capillograph), the set temperature was 160 ° C., the piston descending speed was set to 10 mm / min, the stretch ratio was set to 47, and the load (mN) required for take-up was measured as the melt tension (MS ₁₆₀ ).
(3) Stretchability When the melt tension was measured, the case where the maximum stretch ratio was 4.7 or more was marked with ○ as the workability modifier because the stretchability was poor when the maximum stretch ratio was less than 4.7.
(4) Oxygen concentration In the case of an extruder, the oxygen concentration in the mixing chamber immediately before kneading was measured using an oxygen concentration meter (XP-3180 manufactured by New Cosmos Electric Co., Ltd.) in the case of a Banbury mixer.
(5) Filling rate In the case of an extruder, the volume of the space between the extruder barrel and the screw is calculated, and in the case of a Banbury mixer, the volume of the space between the mixing chamber and the rotor is calculated, The volume was calculated by dividing by the volume of space.
(6) Molecular weight distribution The number average molecular weight (Mn) and the weight average molecular weight (Mw) were measured by the GPC method.

  A solvent in which 0.1% of BHT (manufactured by Wako Pure Chemical Industries, Ltd.) is added as an antioxidant to HPLC grade 1,2,4-trichlorobenzene (manufactured by Wako Pure Chemical Industries, Ltd.) after weighing the measurement sample. In addition to the sample solution, the sample solution was dissolved by shaking at 140 ° C. for 1 hour.

  Using Tosoh Co., Ltd. HLC-8121GPC / HT as a measuring device, it measured as follows. Three TSKgelGMHHR-H (20) HT (manufactured by Tosoh Corporation, inner diameter 7.8 mm, length 30 cm) were connected and used as a separation column. For the moving layer, HPLC grade 1,2,4-trichlorobenzene (Wako Pure Chemical Industries, Ltd.) with 0.05% BHT (Wako Pure Chemical Industries, Ltd.) added as an antioxidant is used. And moved through a separation column maintained at 140 ° C. at a flow rate of 1.0 mL / min. 0.3 mL of a sample solution whose concentration was adjusted to 1.0 mg / mL was injected into this, and sample components separated by a differential refractometer were detected. A molecular weight distribution curve, a number average molecular weight (Mn), and a weight average molecular weight (Mw) were calculated using a quintic approximation curve prepared using standard polystyrene (manufactured by Tosoh Corporation) as a calibration curve.

  Mw / Mn ratio Mw / Mn was calculated and used as an index of molecular weight distribution.

Example 1
As a kneading machine, an intermeshing screw, a counter-rotating type twin screw extruder (Toyo Seiki Seisakusho, trade name: Labo Plast Mill 2D25S type), melt mass flow rate 1.6 g / 10 min, density 919 kg / m ³ High-pressure method low-density polyethylene (manufactured by Tosoh Corporation, Petrocene 360) is melted under the conditions of a kneading temperature of 160 ° C., a discharge rate of 1.7 kg / hour, a screw speed of 60 rpm, an oxygen concentration of 21%, and a filling rate of 80%. The mixture was kneaded, extruded into a strand shape, and formed into pellets using a strand cutter (manufactured by Seiwa Iron Works). The screw used was a multi-flight flight type reverse lead (2S25R type). Table 1 shows the kneading conditions and the measurement results of the melt tension. The Mw / Mn value of the olefinic resin processability modifier was 10.0.

20/80 ratio of the obtained pellets and a linear low density polyethylene having a melt mass flow rate of 20 g / 10 min and a density of 936 kg / m ³ (manufactured by Tosoh Corporation, Nipolon-LM70K, hereinafter referred to as LL-A) And then a strand cutter (Co., Ltd.) using a single screw extruder (made by Plako Co., Ltd.) having a 50 mmφ screw and a strand die and extruding into a strand at a set temperature of 160 ° C. and a discharge rate of 25 kg / hour. (Made by Wako Works) to obtain pellets. Table 1 shows the measurement results of MS ₁₆₀ for this mixture.

Example 2
A high-pressure low-density polyethylene was melt-kneaded under the same conditions as in Example 1 except that the kneading temperature was 200 ° C. The kneading conditions and melt tension are shown in Table 1.

Example 3
High-pressure low-density polyethylene was melt-kneaded under the same conditions as in Example 1 except that the oxygen concentration was 5%. The kneading conditions and melt tension are shown in Table 1.

Example 4
A high-pressure low-density polyethylene was melt-kneaded under the same conditions as in Example 1 except that the filling rate was 50%. The kneading conditions and melt tension are shown in Table 1.

Example 5
As a kneading machine, a Banbury mixer (manufactured by Minami Senju Seisakusho) was used, and melt kneading was performed at a kneading temperature of 160 ° C., an oxygen concentration of 21%, and a filling rate of 75%. The melt-kneaded resin was extruded into a strand shape at a set temperature of 180 ° C. and a discharge rate of 25 kg / hour using a single-screw extruder having a 50 mmφ screw and a strand die (manufactured by Placo Corporation). (Made by Wako Works) to obtain pellets. The kneading conditions and melt tension are shown in Table 1.

比較例１
メルトマスフローレート１．６ｇ／１０分、密度９１９ｋｇ／ｍ^３の高圧法低密度ポリエチレン（東ソー（株）製、ペトロセン３６０）とＬＬ−Ａを２０／８０の割合でドライブレンドし、５０ｍｍφのスクリューとストランドダイを有する単軸押出機（（株）プラコー製）を用いて設定温度１６０℃、吐出量２５ｋｇ／時でストランド状に押出し、ストランドカッター（（株）誠和鉄工所製）を用いてペレットとした。この混合物について、ＭＳ_１６０を測定した。結果を表２に示す。

Comparative Example 1
A melt mass flow rate of 1.6 g / 10 min, a high pressure method low density polyethylene (Tosoh Co., Ltd., Petrocene 360) with a density of 919 kg / m ³ and LL-A are dry blended at a ratio of 20/80, and a 50 mmφ screw Extruded into a strand shape at a set temperature of 160 ° C. and a discharge rate of 25 kg / hour using a single-screw extruder having a strand die (manufactured by Placo) It was. MS ₁₆₀ was measured for this mixture. The results are shown in Table 2.

Comparative Example 2
In Example 1, high-pressure low-density polyethylene was melt-kneaded under the same conditions as in Example 1 except that the kneading temperature was 260 ° C. The kneading conditions and the melt tension before and after the melt kneading are shown in Table 2, but the stretchability was poor and the melt tension could not be measured.

Comparative Example 3
In Example 1, high-pressure low-density polyethylene was melt-kneaded under the same conditions as in Example 1 except that nitrogen was introduced into the extruder so that the oxygen concentration was less than 0.1%, and MS ₂₆₀ was measured. This material was mixed with linear low density polyethylene in the same manner as in Example 1, and MS ₁₆₀ was measured. The results are shown in Table 2, and the melt tension was low.

Comparative Example 4
In Example 1, high-pressure low-density polyethylene was melt-kneaded under the same conditions as in Example 1 except that oxygen was introduced into the extruder to make the oxygen concentration 25%. The kneading conditions and the melt tension before and after melting are shown in Table 2, but the stretchability was poor and the melt tension could not be measured.

Comparative Example 5
In Example 1, high-pressure low-density polyethylene was melt-kneaded under the same conditions as in Example 1 except that the discharge rate was 2.2 kg / hour and the filling rate was 98%, and MS ₂₆₀ was measured. This material was mixed with linear low density polyethylene in the same manner as in Example 1, and MS ₁₆₀ was measured. The results are shown in Table 2, and the melt tension was low.

Comparative Example 6
As a kneading machine, a 20 mmφ single-screw extruder (Toyo Seiki Seisakusho, trade name: Labo Plast Mill) was used. High-pressure low-density polyethylene (Tosoh Corporation) with a melt mass flow rate of 1.6 g / 10 min and a density of 919 kg / m ^3. ), Petrocene 360) was melt kneaded at a kneading temperature of 160 ° C., a discharge rate of 1.7 kg / hour, an oxygen concentration of 21%, and a filling rate of 100%, and MS ₂₆₀ was measured. This material was mixed with linear low density polyethylene in the same manner as in Example 1, and MS ₁₆₀ was measured. The results are shown in Table 2, and the melt tension was low.

Claims (5)

An olefin-based resin processability modifier comprising high-pressure method low-density polyethylene and satisfying the following (A) to (B).
(A) The melt tension at 260 ° C. measured with a capillary viscometer is 145 mN or more. (B) The melt resin can be stretched at a stretch ratio of 4.7 or more under the conditions of measuring the melt tension with a capillary viscometer at 260 ° C. The olefin-based resin processability modifier according to claim 1, wherein the following (G) is satisfied.
(G) Ratio Mw / Mn of weight average molecular weight Mw and number average molecular weight Mn is 6 or more The method for producing an olefin-based resin processability modifier according to claim 1 or 2, wherein high-pressure low-density polyethylene is melt-kneaded under conditions satisfying the following (C) to (E).
(C) Kneading temperature is 130 ° C. or more and 220 ° C. or less (D) Oxygen concentration is 0.1% or more and 21% or less (E) The filling rate of the molten resin in the kneading chamber is 40% or more and 90% or less Furthermore, the manufacturing method of the olefin resin processability modifier of Claim 3 characterized by melt-kneading the high pressure process low density polyethylene on the conditions which satisfy | fill the following (F).
(F) The kneading device is a twin screw extruder or Banbury mixer A resin composition comprising the olefinic resin processability modifier according to claim 1 or 2.