JP2002219710A - Method for manufacturing master batch for modifying resin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To establish a method for continuously and stably manufacturing a master batch containing a large amount of polyisobutylene over a long time. SOLUTION: In the method for manufacturing the master batch for modifying a resin by continuously melting a polyolefin while continuously transferring the same in a continuous kneader and continuously adding polyisobutylene to the transferred molten polyolefin to continuously knead the same with the polyolefin, when the temperature of the molten polyolefin at the polyisobutylene adding place is set to T1, the relative viscosity of the polyolefin corresponding to a zero shearing speed at the temperature T1 is set to 10,000-1,000 Pa.s.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for efficiently and continuously producing a polyisobutylene masterbatch for resin modification comprising a polyolefin and polyisobutylene. More specifically, the present invention relates to a method of kneading and extruding polyisobutylene with a polyolefin to granulate.

[0002]

2. Description of the Related Art Polyolefin resins are molded from various properties by injection molding, extrusion molding, blow molding, inflation molding, etc. due to their excellent physical properties.
Sheets, films and the like are manufactured and industrially consumed on a large scale. And, in order to additionally provide the properties required for each application to the polyolefin resin,
Various modifiers such as liquid or solid powder, for example, a plasticizer,
Fillers, dyes, pigments, lubricants, and antioxidants may be included. These modifiers are directly blended with the polyolefin resin and pelletized for molding, or a masterbatch pellet containing a large amount of the modifier is manufactured in advance, and dried in a polyolefin resin as a base resin during molding. Blend, dilute and use.

[0003] Attempts to add polyisobutylene to polyolefins for modification have been made for a long time. For example, Japanese Patent Publication No. 42224/1972 discloses production of a modified film by adding polyisobutylene to polypropylene. However, since there was no effective means for adding polyisobutylene, polyisobutylene was directly added to polypropylene by a batch system such as a Banbury mixer and kneaded to obtain a mixture, which was then subjected to molding.
In this method, it is necessary to knead all of the materials once before the material is subjected to molding, and since the method is a batch type, the number of steps is increased, which is disadvantageous in cost. To solve this problem, a masterbatch containing a large amount of polyisobutylene has been desired, but there has been no effective production method.

[0004]

SUMMARY OF THE INVENTION In view of the above situation, an object of the present invention is to establish a method for continuously and stably producing a masterbatch containing a large amount of polyisobutylene for a long time.

[0005]

Means for Solving the Problems As a result of intensive studies to solve the above problems, the present inventor has found that a polyolefin resin is heated and melted in advance to a certain viscosity or less, and polyisobutylene is continuously supplied thereto. It has been found that by kneading, it is possible to continuously and stably produce a masterbatch containing a large amount of polyisobutylene, and the present invention has been achieved.

That is, in the first method for producing a masterbatch for resin modification of the present invention, the polyolefin is continuously melted while being continuously transferred in a continuous kneading apparatus. A method of continuously adding isobutylene and kneading them continuously. When the temperature of the molten polyolefin at the place where polyisobutylene is added is T1, the relative viscosity of the polyolefin corresponding to the zero shear rate of T1 is 10,
It is not more than 000 Pa · sec and not less than 1,000 Pa · sec.

The temperature of the kneaded product of polyolefin and polyisobutylene in the continuous kneading apparatus is preferably maintained at a temperature not lower than the melting point (Tm) of the polyolefin and not higher than (Tm + 50) ° C. Preferably, the viscosity average molecular weight of the polyisobutylene is in the range of 5,000 to 1,400,000,
The weight ratio of the polyolefin and polyisobutylene in the obtained masterbatch is 100 to 100% by weight, and is in the range of 30 to 95% by weight and 5 to 70% by weight respectively.

Further, it is preferable to forcibly knead the molten polyolefin and the polyisobutylene at at least one place in the continuous kneading apparatus. Here, "forcibly kneading" means kneading using a kneader such as a screw.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail. In the present invention, the polyolefin and the polyisobutylene are kneaded. Here, "polyolefin" referred to in the present specification includes:
Does not contain polyisobutylene. Examples of the polyolefin used in the present invention are homopolymers or copolymers of olefins such as ethylene, propylene, isobutylene, butene-1, hexene-1, 4-methyl-pentene-1, and octene-1 (however, Excluding isobutylene homopolymer). Examples of preferred polyolefins are low-density polyethylene produced by a high-pressure radical polymerization method, linear low-density polyethylene produced by a high-pressure to low-pressure ionic polymerization method, or propylene homopolymerization or 2 to 2 carbon atoms other than propylene and propylene. This is a polypropylene obtained by copolymerizing 12 α-olefins (hereinafter simply referred to as “α-olefins”). These polyolefins can be used alone or in combination of two or more.

The polyisobutylene used in the present invention is for modifying a resin, particularly a thermoplastic resin such as polyolefin, and can be selected from a wide range depending on the modification application.

For example, concretely, isobutylene, a butane-butene fraction obtained by removing butadiene from a C4 fraction industrially usually obtained during naphtha cracking, or a mixture thereof is treated with aluminum chloride, boron trifluoride, silica or the like. A viscous polymer obtained by polymerization in the presence of an acidic catalyst such as alumina or a cation exchange resin, particularly a Friedel-Crafts type catalyst can be used. These polyisobutylenes preferably have a viscosity average molecular weight of 5,000 to 1,4.
00,000, more preferably 6,000 to 800,0
00 is used. Viscosity average molecular weight of 5,000
Smaller polyisobutylenes are not preferred because they can cause blocking and bleed. Polyisobutylene having a viscosity-average molecular weight of more than 1,400,000 is not preferred because it is too hard to handle and the essential resin modifying effect is diminished. Two or more polyisobutylenes may be used in combination as long as the viscosity average molecular weight is within the above range. Polybutene can be used in an appropriate ratio as long as the effects of the present invention are not impaired.

The mixing ratio of the polyolefin and polyisobutylene used in the present invention is 100% by weight of the total of both.
Is preferably 30 to 95% by weight, more preferably 40 to 90% by weight, still more preferably 45 to 90% by weight, and polyisobutylene is preferably 5 to 70% by weight, more preferably 10 to 60% by weight. %, Still more preferably 10 to 55% by weight. If the amount of polyisobutylene is less than 5% by weight, the significance as a master batch becomes weak, and the resin modification efficiency becomes poor. On the other hand, if the blending amount of polyisobutylene is more than 70% by weight, the surface of the master batch becomes sticky, which is not preferable.

In the present invention, the masterbatch for resin modification is prepared by continuously supplying the above-mentioned polyolefin and polyisobutylene to a continuous kneading extruder so as to have a predetermined mixing ratio, and continuously kneading and pressing. It is obtained by putting out. Here, “continuous” means that the system is not a batch system. The shape of the masterbatch is not particularly limited, but is usually preferably in the form of pellets from the viewpoint of ease of handling. Any known technique for pelletizing the resin can be used for these kneading and extrusion. A typical example is a kneading / extrusion method using a single-screw extruder, a twin-screw extruder, or a kneader ruder (a device in which a kneader is attached to an extruder). What is necessary is just to provide the liquid addition part in the middle stage of the extruder in order to supply polyisobutylene by a pump. The liquid addition section may be of a pressure injection type using a pressure pump, but may be injected at normal pressure using a vent port. Preferably, a twin-screw extruder having at least one kneading zone between the liquid addition section and the die is used. As another extruder, there is a stone-type kneader or the like in which high shear is applied. However, too high shear is not preferable because not only polyisobutylene but also polyolefin resin may be deteriorated and cut.

In the present invention, generally, polyisobutylene is continuously supplied to a continuous kneading extruder using a high-viscosity liquid transfer pump. Known pumps such as a gear pump and a mono pump can be used as the pump for transferring the high-viscosity liquid. Since polyisobutylene has too high a viscosity at room temperature, it is heated and reduced in viscosity to be inserted into a pump. However, at a high temperature of 200 ° C. or higher, polyisobutylene starts to decompose or undergoes oxidative deterioration, which is not preferable. Therefore, it is desirable to insert polyisobutylene at a low temperature as long as the performance of the pump permits.

In the method for producing a masterbatch according to the present invention, the polyolefin charged into the continuous kneading extruder is subjected to a zero shear viscosity of 10,000 Pa · sec.
a. Seconds, melted at a temperature T1 ° C. and transferred to a liquid addition section provided in the middle stage of the same machine, heated polyisobutylene is charged into the liquid addition section, and the two are combined and melt-kneaded and extruded. Is preferred. If the zero-shear viscosity of the heat-melted polyolefin is higher than 10,000 Pa · s, kneading with polyisobutylene may be insufficient. On the other hand, when the viscosity is lower than 1,000 Pa · sec, the viscosity of the mixture becomes too low and the kneading becomes insufficient, and the extruded strands and pellets may be sticky. In addition, in order to lower the viscosity of the molten polyolefin, it is necessary to keep the resin at a high temperature, which may lead to decomposition of the polyolefin, which is not preferable.
The zero shear viscosity of the polyolefin is determined by a commonly used measuring instrument such as a capillary rheometer or a dynamic rheometer.

In the present invention, it is important to directly measure the temperature of the polyolefin at the place where the polyisobutylene is injected, and the temperature of the polyolefin at the place is directly measured and is defined as T1. Specifically, a temperature measuring device is installed, and manufacturing is performed while maintaining the temperature T1 in an appropriate range. There is no particular limitation on the temperature measuring device. Specific examples include, for example, installing a thermocouple at the relevant portion and performing temperature measurement using infrared rays through a glass window.

In the method of the present invention, assuming that the melting point of the polyolefin used is Tm (° C.), the temperature of the kneaded product of the polyolefin and polyisobutylene in the continuous kneading extruder is preferably from Tm ° C. to (Tm + 50) ° C., more preferably Is maintained at Tm ° C or higher and (Tm + 30) ° C or lower. If the temperature of the resin during kneading is higher than (Tm + 50) ° C., the extruded strands and pellets may be sticky. In order to maintain the temperature of the kneaded resin, it is usually preferable to measure the temperature of the kneaded resin itself. However, if it is difficult, the temperature of the kneaded resin is kept within the above range by measuring the temperature of the continuous kneading extruder and the die. To keep. At that time, the resin generally generates heat due to shearing due to kneading, and the temperature of the kneaded resin is considerably higher than the set temperature of the extruder.

In the step of pelletizing the strand obtained by continuous kneading and extrusion, any known technique for cutting the strand can be used. A typical example is a cold cut method, that is, a method in which a strand extruded under the above conditions is cooled by water cooling or air cooling, and then cut by a pelletizer. In addition, it is also possible to extrude in a form other than the strand shape as needed, and cut this into pellets.

It is desirable to cut the strands and the like after cooling to as low a temperature as possible, since pellets can be satisfactorily pelletized without stickiness. It is sufficient to cool the strand surface temperature to less than 10 ° C.

In the method of the present invention, other additional components can be added as long as the effects of the present invention are not impaired. Conventionally known, for example, plasticizers, fillers, dyes, pigments, lubricants, nucleating agents, antioxidants, and the like, aliphatic, aromatic and alicyclic petroleum resins, terpene resins, rosin and the like Tackifying resins such as derivatives can be added. These may be blended in advance with each component of the masterbatch, or may be added during the production of the masterbatch.

When the polyisobutylene masterbatch for resin modification obtained by the production method of the present invention is used, the polyisobutylene masterbatch is appropriately mixed with a polyolefin or other thermoplastic resin to be modified so as to have a predetermined ratio. A product can be obtained by various conventionally known molding methods.

The polyisobutylene masterbatch for resin modification obtained by the production method of the present invention has a very wide range of application. For example, (a) various packaging films (wrap films, stretch films, agricultural films, etc.) (b) various sheets (c) coating materials (d) sound insulation materials, vibration damping materials, sealing materials, waterproofing materials (e) ) Footwear (f) Adhesion (tack), plasticity, flexibility, impact resistance, transparency, etc. to thermoplastic resins used in various fields such as hoses and packing materials, especially products made of polyolefin materials Is useful as a modifier for imparting the properties of Such a polyolefin to be modified is not particularly limited, but generally, the above-described low-density polyethylene, ethylene-vinyl acetate copolymer, high-density polyethylene, linear low-density polyethylene, homo, block, or random polypropylene is used. Is exemplified.

[0023]

The present invention will be described below in more detail with reference to examples. First, the differential scanning calorimetry (D
SC) and methods, materials and devices for measuring various practical performances will be described.

Measurement Methods of Various Properties (1) Differential Scanning Calorimetry (DSC) Thickness 100 obtained by hot press molding of polyolefin
A μm film was used as a sample, which was heated to 230 ° C. and held at that temperature for 10 minutes, and then cooled at a rate of 10 ° C./min.
Cool to 0 ° C. Next, from this state, the heating rate is 10 ° C. /
The temperature is raised to 230 ° C. in minutes and the measurement is performed. 30 ° C to 2
The maximum peak temperature (Tm) is defined as the peak position of the maximum peak among the peaks that appear during the temperature rise to 30 ° C., and is defined as the melting point of the polyolefin. When two or more types of polyolefins are used as a mixture, the polyolefin mixture is measured in accordance with the ratio finally added, and the maximum peak temperature, that is, the melting point (Tm), is determined by determining the position of the highest peak among all the peaks that appear. And

(2) Zero Shear Viscosity Measurement Method The dynamic viscoelasticity of a polyolefin was measured using a UDS-200 type rheometer manufactured by Paar Physica Co., Ltd. Zero shear viscosity was determined assuming equality. Using a parallel disc-shaped jig having a diameter of 25 mm as a measuring jig and performing preheating for 2 hours or more at a predetermined temperature, all were in the range of strain = 10% and angular frequency ω = 0.01 to 100 radians / sec. Was measured. The test piece was prepared by preparing a sheet having a thickness of 2 mm by press molding and cutting out the sheet to a predetermined size.

(3) Method for evaluating stickiness of pellets A strand having a length of about 50 mm is sandwiched between two transparent polyester films (38 μm in thickness) and gently pressed down with a fingertip. From the traces of the strands remaining on the polyester film, The degree of stickiness was determined according to the following criteria. ：: No stickiness (no trace left at all) ○: Almost no (slight trace remains) △: Medium stickiness (some trace remains) ×: Yes (a trace remains over the whole surface) ××: Sticky severe (separation) Can be seen visually)

(4) Method for Evaluating Pellet Formability In extruding a strand from a kneading machine and performing cutting after cooling, the evaluation of the formability was determined according to the following criteria. A: Molding was completed without any problem. ：: The strand was slightly sticky, but could be molded almost without any problem. Δ: Some surging was observed, but continuous molding was possible by adjusting the conditions. X: The strand was easily broken due to insufficient kneading. XX: Kneading was completely insufficient, and it was difficult to form continuously.

Polyolefins The homopolypropylenes A1 and A2 and the propylene / ethylene random copolymer A3 whose properties are shown in Table 1 were used in Examples and Comparative Examples.

[0029]

[Table 1]

Kneading extruder used for the production of master batch (a) KTX-30 type twin screw extruder manufactured by Kobe Steel Ltd .: Same direction, meshing type. Screw diameter 30mmφ, L / D = 3
7. Two kneading zones. (B) Single screw extruder: full flight screw, screw diameter 50 mmφ, L / D = 24. Pump used for supplying polyisobutylene (c) Monono pump 3NTL10 manufactured by Hyojinki

Example 1 Two barrels from the hopper port provided at one end of the twin-screw extruder (a) to the vent port provided in front of the kneading zone were used.
At 10 ° C., the barrel from the vent port to the die provided at the other end of the extruder was kept at 160 ° C., and polypropylene A1 was charged from the hopper port. Nitrogen gas was passed through the vent to prevent oxygen from entering the barrel. The temperature of the resin passing through the barrel near the vent was measured to be 230 ° C. The zero shear viscosity at 230 ° C. of the polypropylene A1 was 4,500 Pa · sec.

Separately, polyisobutylene (viscosity average molecular weight 30,000), which had been heated to 180 ° C. in advance, was continuously supplied to the extruder from the vent port of the extruder using the pump (c). The experiment was performed such that the amount of polyisobutylene was 40% by weight in the resulting masterbatch.
The kneading and extrusion of the polypropylene A1 and polyisobutylene were performed at a screw rotation speed of 200 rpm and the temperature conditions shown in Table 2. Under the above conditions, the operation of the twin-screw extruder was
Continuously, the strand was continuously extruded from the die and passed through a water bath cooled to 4 ° C. for about 15 seconds. The surface temperature of the strand was 6 to 8 ° C. This was cut continuously to obtain pellets. The pellet obtained after 2 hours was further aged at 60 ° C. for 48 hours. Table 2 shows the property evaluation results of the pellets before and after aging.

In this experiment, stable (uniform) pellets of stable properties were obtained continuously for 2 hours, and no mechanical problems occurred. That is, the extruder operated smoothly without clogging of the resin or breaking of the strand due to surging or the like. The aged pellets also showed good properties.

Example 2 The experiment was repeated in the same manner as in Example 1 except that the polypropylene was changed to A2 and the barrel from the hopper port to the vent port of the twin-screw extruder (a) was kept at 230 ° C. 2 is shown. The temperature of the resin passing through the barrel near the vent was 250 ° C. 250 ° C of polypropylene A2
At 5,000 Pa · sec.
In this experiment, stable pellets were continuously obtained for 2 hours without any mechanical problems.
The aged pellets also showed good properties.

Example 3 In Example 1, the polypropylene was changed to A3, and the barrel from the vent port of the twin screw extruder (a) to the die was 140
The experiment was repeated in the same manner except that the temperature was kept at ℃, and the results are shown in Table 2. The temperature of the resin passing through the barrel near the vent is 2
30 ° C. The zero shear viscosity at 230 ° C. of the polypropylene A3 was 5,000 Pa · sec. In this experiment, stable pellets were continuously obtained for 2 hours without any mechanical problems. The aged pellets also showed good properties.

Example 4 In Example 1, the barrel temperature of the kneader was changed to 210
An experiment was conducted in the same manner except that the temperature was set to ° C., and the results are shown in Table 2. The temperature of the resin passing through the barrel near the vent is 23
It was 0 ° C. In this experiment, although the strands were slightly sticky, pellets having stable properties were continuously obtained for 2 hours, and no particular mechanical problem occurred. When the pellets were aged, stickiness was slightly higher than in Examples 1 to 3.

Example 5 In Example 1, the kneading machine was changed to a single screw extruder (b).
The same experiment was conducted except that polyisobutylene was injected under pressure from the liquid addition section provided in the middle stage of the extruder (having no vent port), and the results are shown in Table 2. In addition, since there was no resin temperature measuring device near the liquid addition part, the molten resin temperature in the vicinity was not measured. In this experiment, although the strand was slightly sticky, pellets having stable properties were continuously obtained for 2 hours, and no particular mechanical problem occurred. When aging was performed on the pellets, Example 1 was obtained.
３3 slightly more sticky.

Comparative Example 1 In the same manner as in Example 1, except that the barrel from the hopper port to the vent port of the twin-screw extruder (a) was kept at 150 ° C. and the barrel from the vent port to the die was kept at 160 ° C. And the results are shown in Table 2. The temperature of the resin passing through the barrel near the vent was 180 ° C. Polypropylene A1
Has a zero shear viscosity at 180 ° C of 18,000 Pa ·
Seconds. In this experiment, the kneading became insufficient, the extrusion became uneven, and the strands were easily cut.
Difficulties arose in producing pellets continuously. The produced pellets also showed slightly more stickiness than Examples 1-3.

[0039] In Comparative Example 2 Example 1, the barrel from the hopper port of a biaxial extruder (a) to vent to 0.99 ° C., the barrel from the vent port to the die was maintained at 160 ° C., the polypropylene A2 biaxial An experiment was conducted in the same manner except that the extruder (a) was charged through the hopper port, and the results are shown in Table 2. The temperature of the resin passing through the barrel near the vent was 180 ° C. The zero shear viscosity at 180 ° C. of polypropylene A2 is 32,0
00 Pa · sec. In this experiment, kneading was further insufficient than in Comparative Example 1, and pellets could not be produced continuously.

[0040] In Comparative Example 3 Example 1, the barrel from the hopper port of a biaxial extruder (a) to vent to 0.99 ° C., the barrel from the vent port to the die was maintained at 140 ° C., the polypropylene A3 biaxial An experiment was conducted in the same manner except that the extruder (a) was charged through the hopper port, and the results are shown in Table 2. The temperature of the resin passing through the barrel near the vent was 180 ° C. The zero shear viscosity at 180 ° C. of polypropylene A3 is 19,0
00 Pa · sec. Also in this experiment, Comparative Example 1
Similarly to the case described above, the kneading was insufficient, the extrusion was uneven, and the strands were easily cut. Thus, it was difficult to continuously produce pellets. Example 1 produced pellets
３3 slightly more sticky.

Comparative Example 4 An experiment was conducted in the same manner as in Example 5 except that the barrel from the hopper port of the single screw extruder (b) to the liquid addition section was kept at 150 ° C. Also in this experiment, kneading was insufficient as in Comparative Example 2, and pellets could not be produced continuously.

[0042]

[Table 2]

[0043]

According to the method of the present invention, a polyisobutylene masterbatch for modifying a thermoplastic resin in which a polyolefin and polyisobutylene are sufficiently kneaded can be continuously and stably produced for a long time. As a result, a polyisobutylene masterbatch pellet for thermoplastic resin modification with less occurrence of blocking (stickiness) and the like can be efficiently obtained.

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Claims (4)

[Claims] 1. A continuous kneading apparatus in which a polyolefin is continuously melted while being continuously transferred, polyisobutylene is continuously added to the transferred molten polyolefin, and these are continuously kneaded. A method for producing a masterbatch for resin modification, wherein, when the temperature of a molten polyolefin at a place where polyisobutylene is added is T1, the relative viscosity of the polyolefin corresponding to the zero shear rate of T1 is 10,000 Pa · sec or less. , 00
A method for producing a master batch for resin modification, which is at least 0 Pa · sec. 2. The method according to claim 1, wherein the temperature of the kneaded product of the polyolefin and the polyisobutylene in the continuous kneading apparatus is maintained at a temperature not lower than the melting point (Tm) of the polyolefin and not higher than (Tm + 50) ° C. 3. The viscosity-average molecular weight of the polyisobutylene is in the range of 5,000 to 1,400,000, and the weight ratio of the polyolefin and the polyisobutylene in the obtained masterbatch is 100% by weight in total. 3. The method according to claim 1, wherein the content is in the range of 30 to 95% by weight and 5 to 70% by weight. 4. The method according to claim 1, wherein the molten polyolefin and the polyisobutylene are forcibly kneaded in at least one place in the continuous kneading apparatus.