JP5371253B2 - Method for producing thermoplastic resin composition containing liquid additive - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thermoplastic resin composition in which a liquid additive and a thermoplastic resin material in a pellet form are nearly uniformly dispersed and good extrusion properties can be exhibited without causing autohesion etc., in a hopper when used as an extrusion material in the thermoplastic resin composition comprising the liquid additive and the thermoplastic resin in the pellet form, to provide the thermoplastic resin composition formed by a method for production with a small number of steps as compared with the conventional technique which is the method for producing the thermoplastic resin composition, and to provide the method for producing the thermoplastic resin composition. <P>SOLUTION: The thermoplastic resin composition is prepared by further using an inorganic filler having a &ge;0.1 to &le;10 &mu;m weight-average particle diameter, a product of &ge;10 of the weight-average particle diameter (&mu;m) and the specific surface area (m<SP>2</SP>/g), and &ge;40 ml/100 g boiled linseed oil absorption, and simultaneously mixing the thermoplastic resin in the pellet form with the inorganic filler, and the liquid additive in a specific compounding ratio when the thermoplastic resin in the pellet form is mixed with the liquid additive. <P>COPYRIGHT: (C)2009,JPO&amp;INPIT

Description

The present invention relates to a method for producing a thermoplastic resin sets formed containing the liquid additive to be used for molding the resin molded article by extrusion molding, and more particularly, a thermoplastic resin pellet shape, a plasticizer, the method for producing a resin sets formed containing a liquid additive such as a flame retardant.

Conventionally, when a resin molded product is molded, it is generally performed to use a liquid additive for imparting a specific function such as resin hardness adjustment or flame retardancy together with a thermoplastic resin material. .

  However, the use of the above liquid additive is, for example, by kneading the molding material in advance before molding, such as a calendar method in which the resin material and the liquid additive are previously melt-kneaded in a banbury and then put into a molding machine. Although the composition may be molded, the extrusion molding method in which a pellet-shaped thermoplastic resin such as polyolefin or polyester (hereinafter also simply referred to as “pellet-shaped resin”) is charged into a hopper has the following problems. That is, in the case where the pellet-shaped resin and the liquid additive are put into one hopper in the extrusion molding apparatus, there is a problem that the surface of the pellet-shaped resin becomes wet and the pellet-shaped resins adhere to each other. In some cases, a part of the liquid additive is separated and collected at the outlet of the hopper. Moreover, even if the pellet resin and the liquid additive are simply mixed, it is difficult to uniformly mix the two. Therefore, in the process in which the pellet resin is melted in the screw, the liquid additive is uniformly distributed. There was a problem that it was difficult to mix.

  On the other hand, a side feed device is provided in the extrusion molding device, and an extrusion molding device is prepared by adding a liquid additive from the side feed device to the pellet-like resin supplied from the hopper into the extrusion molding device and mixing them. The use of an extrusion apparatus (hereinafter, also referred to as “prior art 1”) that enables a resin material to be master-batched has been reported (for example, Patent Documents 1 and 2 below).

  Another attempt is to uniformly disperse the liquid compound in the thermoplastic resin material by mixing and extruding the particulate thermoplastic resin, the powdered thermoplastic resin, and the liquid additive in a specific order. An invention of a method for producing a liquid additive-containing thermoplastic resin (hereinafter also referred to as “Prior Art 2”) has been reported (hereinafter also referred to as “Prior Art 2”). 3). Alternatively, a liquid substance, 0.5 to 10 times the amount of pellet-like thermoplastic resin particles in a weight ratio, and 0.5 to 10 times the amount of non-pellet-like thermoplastic resin particles in the same weight ratio are mixed. Thus, an invention of a method of mixing a liquid substance and thermoplastic resin particles (hereinafter also referred to as “Prior Art 3”) capable of uniformly mixing and dispersing them has been reported (Patent Document 4 below). Alternatively, after the liquid additive is first adsorbed on a compound having a number average particle diameter of 0.001 to 50 μm, the liquid adsorbed compound is then mixed with a thermoplastic resin. Has been reported (hereinafter, also referred to as “prior art 4”).

Japanese Examined Patent Publication No. 47-40852 Japanese Patent Publication No.46-10998 JP 61-188424 A Japanese Patent Laid-Open No. 62-112628 JP 09-241422 A

  However, the prior arts 1 to 4 have the following problems. That is, the prior art 1 has a problem in terms of cost because it requires a special extrusion molding apparatus equipped with a side feed device and increases the cost of the apparatus, resulting in an increase in the price of the resulting molded product. .

  Prior art 2 and prior art 3 use both granular thermoplastic resin (pellet-shaped thermoplastic resin particles) and powdered thermoplastic resin (non-pellet-shaped thermoplastic resin particles). In addition, it is necessary to first obtain a granular thermoplastic resin (pellet-shaped thermoplastic resin particles) and pulverize it to obtain a powdered thermoplastic resin (non-pellet-shaped thermoplastic resin particles). For this reason, a special process called a pulverization process is required, which is troublesome and costly.

  Further, both of the prior art 2 and the prior art 4 use a thermoplastic resin material, a liquid additive, and a powdered material. In the prior art 2, the liquid additive is mixed and adhered to the granular thermoplastic resin, and this mixture is used. In addition, a powdered thermoplastic resin (powder material) is further mixed to prepare a resin composition containing a liquid additive. In the prior art 4, a compound having a number average particle diameter of 0.001 to 50 μm After the liquid additive is adsorbed to (powder material), a thermoplastic resin is further mixed into this mixture to prepare a resin composition containing the liquid additive. In other words, in order to obtain a thermoplastic resin composition containing a liquid additive, a thermoplastic resin in which the liquid additive is uniformly mixed with the thermoplastic resin material without passing through a two-step mixing process in a specific order. It was difficult to prepare the composition, and good extrudability could not be obtained. This indicates that in the comparative examples of Patent Document 3 and Patent Document 5 in which Conventional Technology 2 and Conventional Technology 4 are disclosed, when the resin composition material is mixed at the same time, the extrusion molding was defective. It is understood from that. In contrast to the prior arts 2 and 4, there has been a desire to reduce the mixing step to one step, thereby reducing labor and cost.

The present invention has been made in consideration of the above situation and demands, and more particularly, a method of manufacturing the thermoplastic resin of sets formed product and the thermoplastic resin material in liquid additive and pellet was dispersed substantially uniformly Te, it is an object to provide a manufacturing method of the thermoplastic resin composition formed by low manufacturing method of the number of steps compared with the prior art.

  The present inventor, when mixing a pellet-shaped thermoplastic resin and a liquid additive, further uses a specific inorganic filler, and by mixing these simultaneously, the liquid additive and the thermoplastic can be easily mixed. The present inventors have found that a thermoplastic resin composition in which a resin is mixed almost uniformly can be obtained, and the present invention has been completed.

That is, the present invention
(1) A method for producing a thermoplastic resin composition comprising a pellet-shaped thermoplastic resin and a liquid additive,
(A) a pellet-shaped thermoplastic resin;
(B) The weight average particle diameter is 0.1 μm or more and 10 μm or less, the product of the weight average particle diameter (μm) and the specific surface area (m ² / g) is 10 or more, and the boiled linseed oil absorption is 40 ml / 100 g or more. An inorganic filler,
(C) a liquid additive,
With respect to 100 parts by weight of (A), the sum of the parts by weight of (B) and (C) is 15 parts by weight or more and 100 parts by weight or less, and (B) and (C) A thermoplastic resin containing a liquid additive , characterized by having a step of mixing in a mixing device at a blending ratio such that the ratio of parts by weight is (B) / (C) = 1 to 2 Production method of the composition ,
(2) The method for producing a thermoplastic resin composition containing the liquid additive according to (1), wherein the inorganic filler is calcium carbonate ,
Is a summary.

  In the present invention, by using the specific inorganic filler, a liquid additive, a pellet-shaped thermoplastic resin, and the inorganic filler are mixed at the same time, whereby the liquid additive is dispersed substantially uniformly. A plastic resin composition can be obtained. Therefore, in addition to the conventional thermoplastic resin particles in the form of pellets, pellets can be formed as thermoplastic resin without using powdered thermoplastic resin particles obtained by pulverizing the thermoplastic resin particles, and without dividing the mixing process into two steps. A thermoplastic resin composition containing a liquid additive can be easily obtained using only a shaped thermoplastic resin. Alternatively, it is not necessary to use an expensive molding apparatus having a side feed device as in the prior art. As a result, the cost of the resin molded product finally obtained can be kept low.

In the thermoplastic resin composition obtained in the present invention, the liquid additive is dispersed substantially uniformly and is sufficiently absorbed by the inorganic filler specified in the present invention. Wetting on the surface is suppressed. As a result, when the thermoplastic resin composition obtained by the present invention is put into the hopper of an extruder, the pellets do not adhere to each other and block, and good extrusion moldability is exhibited. Processing stability is increased.

  In particular, according to the present invention using specific inorganic filler particles having irregular surface irregularities, there are further advantageous effects. That is, when the thermoplastic resin containing the inorganic filler particles that have absorbed the liquid additive in the mixing step is melted and stirred by a screw in the extrusion molding apparatus, the uneven portions of the inorganic filler particles are caused by shear stress. Crush and disperse more finely in the molten resin. This means that the liquid additive absorbed in the inorganic filler particles is dispersed in the molten resin. That is, the liquid additive is very well dispersed in the resin. Therefore, it is possible to provide a desirable molded product that exhibits the properties of the resin molded product expected by the use of the liquid additive evenly.

  In particular, the inorganic filler in the present invention is made of calcium carbonate, which is advantageous from the viewpoint of its handleability, availability, cost, etc. Among them, the calcium carbonate particles have irregular irregularities on the surface. It is desirable to use an inorganic filler composed of

In addition, the thermoplastic resin composition containing the liquid additive obtained in the present invention has no stickiness and is supplied to the extrusion molding apparatus in a dry state, so that cleaning of the system of the extrusion molding apparatus is very easy. Therefore, the switching operation for molding different resin molded products is efficiently performed.

  The best mode of the present invention will be described below.

(About thermoplastic resin)
The thermoplastic resin used in the present invention can be appropriately selected and used as long as it is a thermoplastic resin that can be molded into a pellet shape. For example, specific examples thereof include polyolefin, polyester, polystyrene, polyamide, polyurethane, polycarbonate, and polyvinyl chloride.

  In the present invention, the pellet-shaped thermoplastic resin refers to a product obtained by molding the above-described thermoplastic resin into a granular resin that exceeds the size generally understood as powder. The shape may be an arbitrary shape such as a substantially spherical shape, an elliptical shape, or a cylindrical shape. Further, the size is not particularly limited, but as a material used for extrusion molding, the maximum diameter is generally about 2 mm or more and 6 mm or less.

(About inorganic fillers)
The inorganic filler used in the present invention can be selected from known inorganic fillers that can be used in resin molding, such as calcium carbonate and talc. However, it is limited to the following conditions.

It is important that the inorganic filler used in the present invention has a product of a weight average particle diameter (μm) and a specific surface area (m ² / g) of 10 or more. The present inventor investigated the correlation between the reciprocal of the weight average particle diameter (μm) and the specific surface area of calcium carbonate as an example in the research process for achieving the object of the present invention. The relationship shown is found. That is, spherical calcium carbonate having no irregularities on the surface, which is generally used as a filler, and having almost no pores, shows the correlation between the reciprocal of its weight average particle diameter (μm) and the specific surface area in the first quadrant. Formula 1 below
(Formula 1) y = 2.613x + 0.3823
Are substantially present on a straight line indicated by and are proportional to each other. On the other hand, some special calcium carbonate did not follow this straight line, but existed in the first quadrant above the straight line, that is, in a region having a large specific surface area value. In the figure, spherical general-purpose calcium carbonate having no irregularities on the surface and almost no pores is shown by a black diamond plot, and special calcium carbonate is shown by a white diamond plot.

  In other words, in the graph of FIG. 1, the general-purpose calcium carbonate existing in a straight line has a product of a weight average particle diameter and a specific surface area of about 2.0 to 2.3, and is expressed by Equation 1. The product of the weight average particle diameter and the specific surface area of special calcium carbonate existing in a region exceeding the straight line was more than 2 while it was substantially assembled on a straight line.

  As a result of further study on the product of the weight average particle size and the specific surface area, the present inventor has found that the inorganic filler having a product of the weight average particle size and the specific surface area of 10 or more has a boiled linseed oil absorption of 40 ml / 100 g. It was found that the above absorbability was very high. And if it is this inorganic filler, when mixed with a pellet-shaped thermoplastic resin and a liquid additive at the same time, the liquid additive is sufficiently absorbed by the inorganic filler, and the inorganic that has absorbed the liquid additive Since the filler adheres to the surface of the pellet-shaped thermoplastic resin and is well dispersed throughout the composition, the resulting thermoplastic resin composition does not become sticky. Therefore, when the thermoplastic resin composition is put into the hopper of the extrusion molding apparatus, the thermoplastic resin composition or the pellets in the composition are not self-attached and the hopper outlet is not clogged. The parts are not separated and the liquid pool is not formed. As a result, when extrusion molding is performed using the thermoplastic resin composition, very good extrusion moldability is exhibited.

  The boiled linseed oil absorption is measured according to the boiled linseed oil method defined in JIS K5101. The boiled linseed oil absorption amount of the inorganic filler usable in the present invention is 40 ml / 100 g or more, preferably 45 ml / 100 g or more, and more preferably 50 ml / 100 g or more.

  In particular, by selecting an inorganic filler whose particle surface is composed of irregular irregularities, the product of the weight average particle diameter and the specific surface area is 10 or more, and the boiled linseed oil absorption is It turned out that the inorganic filler which can be used in this invention which shows 40 ml / 100g or more can be obtained easily.

  In addition, the inorganic filler having a product of the weight average particle diameter and the specific surface area of 10 or more is particularly composed of irregular irregularities on the particle surface among the inorganic filler having boiled linseed oil absorption of 40 ml / 100 g or more. In addition to the effect that a thermoplastic resin composition excellent in extrusion moldability can be obtained, the inorganic filler that is provided has further effects due to its special shape. That is, when the thermoplastic resin composition of the present invention is fed into the screw portion in the extrusion molding apparatus, the inorganic filler is sheared and at least part of the uneven inorganic filler is crushed and melted. It is easy to be further finely dispersed in the plastic resin. At this time, since the liquid additive is absorbed in the inorganic filler, the liquid additive is also dispersed at the same time as a result of the inorganic filler being dispersed in the molten resin. Therefore, as a result of the liquid additive being dispersed very uniformly in the molten thermoplastic resin, a function required by adding the liquid additive (for example, if the liquid additive is a flame retardant) It is possible to obtain a resin molded product imparted with non-uniformity in flame retardancy.

  Here, the inorganic filler whose particle surface is composed of irregular irregularities does not matter whether the particles are porous or not. Irregular irregularities on the particle surface can also be expressed as, for example, “rose petal” or “garlic”. For example, as commercially available products, porous calcium carbonate “CALLITE KT” manufactured by Shiroishi Calcium Co., Ltd., or precipitated calcium carbonate “ALBACAR 5970” manufactured by Pfematech Co., Ltd., etc., has irregular irregularities on the particle surface in the present invention. Can be used as an inorganic filler.

  The weight average particle diameter of the inorganic filler that can be used in the present invention is 0.1 μm or more and 10 μm or less. The preferable range of the weight average particle diameter was determined in consideration of good dispersibility in the thermoplastic resin composition, availability thereof, and the like.

(About liquid additives)
As a liquid additive in this invention, if it is a liquid additive at normal temperature used in order to provide a further function to a thermoplastic resin, it can select suitably and can be used. Examples thereof include plasticizers such as dioctyl phthalate and dioctyl adipate, flame retardants such as phosphate esters, stabilizers such as waxes and styrenated phenols. The liquid additive may be a single additive or a combination of two or more additives.

(About the blending ratio of the thermoplastic resin composition)
In the thermoplastic resin composition obtained in the present invention , the blending ratio of (A) pellet-shaped thermoplastic resin, (B) inorganic filler, and (C) liquid additive is included in the following range. . That is, their blending ratio is (A) 100 parts by weight of the pellet-shaped thermoplastic resin, and the sum of the parts by weight of (B) inorganic filler and (C) liquid additive is 1 to 100 parts by weight, And the ratio of the weight part of (B) inorganic filler and (C) liquid additive is contained in the range which becomes (B) :( C) = 99: 1-50: 50 . Even if the blending ratio is in the range of (B) :( C) = 99: 1 to 50:50 with respect to (A) 100, when (B) + (C) exceeds 100, (A) pellets (B) Inorganic filler that absorbed (C) liquid additive could not adhere to the surface of the shaped thermoplastic resin, and (B) inorganic filler that absorbed a part of (C) liquid additive in the composition The material exists in a separated state, which causes poor extrusion moldability. Further, if the blending ratio of (B) :( C) = 99: 1 to 50:50 is deviated, there is a possibility that the total amount of (C) liquid additive may not be absorbed by (B) inorganic filler, and (A) pellet shape Since there is a risk that the surface of the resin may become sticky or the liquid at the hopper outlet may be accumulated, it may cause a poor extrusion moldability. In addition, when mixing and using 2 or more types of liquid additives, it adjusts so that the sum total of the weight may become the preferable mixture ratio of the (C) liquid additive mentioned above.

Moreover, you may add a desired additive to the thermoplastic resin composition obtained by this invention according to the objective in the range which does not deviate from the meaning of this invention. Examples of the additives include colorants, ultraviolet absorbers, antioxidants, light stabilizers, antistatic agents, hydrolysis inhibitors, organic fillers, inorganic fillers, and the like. However, when these additives are used as a liquid material, the handling thereof shall be handled as the liquid additive in the present invention described above. That is, the liquid additive should be used within a preferable blending amount in the thermoplastic resin composition.

(About manufacturing method)
The greatest feature of the method for producing a thermoplastic resin composition containing the liquid additive of the present invention is that the pellet-shaped thermoplastic resin, the specific inorganic filler described above, and the liquid additive can be mixed simultaneously. In the point.

  The method of mixing the pellet-shaped thermoplastic resin, the specific inorganic filler described above, and the liquid additive can be performed using a commonly used mixing apparatus such as a tumbler mixer or a Henschel mixer. Moreover, even if the temperature in the mixing apparatus at the time of mixing is about room temperature, it is possible to sufficiently mix the three at the same time to obtain a uniform thermoplastic resin composition. A high temperature is preferable because the liquid additive is well absorbed by a filler such as calcium carbonate. The mixing time is appropriately determined depending on the amount to be mixed or the type of composition, temperature, type of mixing apparatus, and the like. In addition, when adding additives other than the above-mentioned pellet-shaped thermoplastic resin, inorganic filler, and liquid additive, the pellet-shaped thermoplastic resin, inorganic filler, and liquid additive are mixed together. Can be mixed.

The thermoplastic resin composition containing the liquid additive obtained in the present invention can be used as a material for molding a resin molded product by an extrusion molding method. As the extrusion molding apparatus, any of extrusion molding apparatuses such as generally used injection molding apparatuses, T-die apparatuses, and inflation apparatuses can be used. In the above thermoplastic resin composition, the liquid additive is sufficiently absorbed by the inorganic filler, and the inorganic filler that has absorbed the liquid additive adheres to the surface of the pellet-shaped thermoplastic resin and is spread over the entire composition. Because it is dispersed, when it is put into the hopper of an extrusion molding device, the thermoplastic resin composition or the pellet-shaped thermoplastic resin contained in the thermoplastic resin composition does not adhere to the hopper outlet part. In addition, there is no possibility that a part of the liquid additive is separated from the thermoplastic resin composition and accumulated in the hopper. Accordingly, the extrusion moldability is good, and the extrusion pressure is kept substantially constant from the start to the end of the extrusion without requiring any special operation, so that a good resin molded product without unevenness can be obtained. . Further, since the liquid additive is dispersed substantially uniformly, the function expected by the addition of the liquid additive is exhibited evenly in the resin molded product.

  EXAMPLES Hereinafter, although this invention is demonstrated more concretely based on an Example and a comparative example, this invention is not limited to a following example.

(Examples 1-7)
Using the materials and ratios (parts by weight) shown in Table 1 as thermoplastic resins, inorganic fillers, and liquid additives, these were simultaneously charged into a Henschel mixer at room temperature, and mixed at a stirring speed of 350 rpm for 10 minutes. A thermoplastic resin composition was prepared, and this was designated as Examples 1-7.

(Comparative Example 1)
Using the thermoplastic resin and liquid additives, the materials and proportions (parts by weight) shown in Table 2, and simultaneously adding them to a Henschel mixer at room temperature, mixing for 10 minutes at a stirring speed of 350 rpm, the thermoplastic resin A composition was prepared and used as Comparative Example 1.

(Comparative Examples 2-6)
A thermoplastic resin composition was prepared in the same manner as in Comparative Example 1 except that the inorganic filler shown in Table 2 was used, and the materials and proportions (parts by weight) shown in Table 2 were used as the thermoplastic resin and liquid additive. It was set as Comparative Examples 2-6.

  The thermoplastic resin composition of Example 1 is put into a hopper of a twin screw extruder (hopper outlet inner diameter: 5 cm, feed device: single screw) having a screw diameter of 30 mm, and melt extrusion is performed at a temperature of 200 ° C. and a discharge speed of 10 kg / h. Processing was performed. The extrusion moldability at this time was evaluated as follows. The evaluation results are shown in Table 1.

  Moreover, about Examples 2-7 and Comparative Examples 1-6 similarly, it injected into the hopper of the said biaxial extruder, and extrusion moldability was evaluated as follows. The evaluation results are shown in Table 1 for Examples 2 to 7 and in Table 2 for Comparative Examples 1 to 6.

  The details of the thermoplastic resin, inorganic filler, and liquid additive shown in Tables 1 and 2 are as follows.

(Thermoplastic resin)
<PE> Petrocene 180 (low density polyethylene, manufactured by Tosoh Corporation)
<PBAT> Ecoflex (Polybutylene adipate terephthalate, manufactured by BASF Japan Ltd.)

(Inorganic filler)
<CALLITE KT> Porous calcium carbonate whose particle surface is composed of irregular irregularities (inorganic filler, manufactured by Shiroishi Calcium Co., Ltd., weight average particle size 2.3 μm, specific surface area 35 m ² / g, weight average particle size And specific surface area: 80.5, oil absorption 70 ml / 100 g)
<ALBACAAR 5970> Precipitated calcium carbonate whose particle surface is composed of irregular irregularities (inorganic filler, manufactured by Pfematotech Co., Ltd., weight average particle size 1.9 μm, specific surface area 7 m ² / g, weight average particle size And the specific surface area: 13.3, the oil absorption is 50 ml / 100 g, and the particle surface is in the shape of rose petals)
<Hightron> Substantially flat porous talc (inorganic filler, manufactured by Takehara Chemical Industries, Ltd., weight average particle diameter 5.0 μm, specific surface area 4.5 m ² / g, product of weight average particle diameter and specific surface area: 22.5, oil absorption 40ml / 100g)
<Vigot 10> Light spherical calcium carbonate having a substantially spherical shape (inorganic filler, manufactured by Shiroishi Kogyo Co., Ltd., weight average particle size 0.17 μm, specific surface area 13.5 m ² / g, product of weight average particle size and specific surface area: 2 .3, Oil absorption 28ml / 100g)
<NS2300> amorphous heavy calcium carbonate (inorganic filler, manufactured by Nitto Flour Chemical Co., Ltd., weight average particle size 0.97 μm, specific surface area 2.3 m ² / g, product of weight average particle size and specific surface area : 2.2, oil absorption 34.5ml / 100g)
The oil absorption amount of the inorganic filler described above is a value measured by the boiled linseed oil method in JIS K5101.

(Liquid additive)
<DOP> bis (2-ethylhexyl) phthalate (plasticizer, manufactured by Daihachi Chemical Industry Co., Ltd.)
<TXP> Phosphate ester (flame retardant, manufactured by Daihachi Chemical Industry Co., Ltd.)

(Formability evaluation 1)
The state in which the thermoplastic resin composition charged into the hopper was extruded to the screw part in the apparatus was evaluated as follows.
A: The thermoplastic resin composition was smoothly fed from the hopper to the screw part.
Δ: A part of the thermoplastic resin composition (or the pellet-like resin in the thermoplastic resin composition) was self-adhering and solidified, and sometimes the hopper outlet was clogged.
X: The thermoplastic resin composition (or the pellet-like resin in the thermoplastic resin composition) was hardened at the hopper outlet, and the extrusion from the hopper to the screw part completely stopped, and the extrusion molding could not be performed.

(Formability evaluation 2)
The molten resin pressure when the thermoplastic resin composition put into the hopper was extruded was observed and evaluated as follows. In addition, the molten resin pressure shown below is a pressure measured immediately before the molten resin passes through a screen mesh installed at the screw tip (die side) in the extrusion molding apparatus.
A: The molten resin pressure was stable from the start to the end of the extrusion process.
X: The molten resin pressure was different between when the extrusion molding process was disclosed and when the extrusion process was completed, and the molten resin pressure during processing was not stable.

  From the above evaluation results, in Examples 1 to 7, self-adhesion of the thermoplastic resin composition or the pellet-like resin contained therein does not occur, and a part of the liquid additive is separated and the inside of the hopper There were no inconveniences such as accumulating. As a result, the thermoplastic resin composition could be smoothly fed into the screw part from the hopper.

In Examples 1 to 7, the molten resin pressure was stable during extrusion molding, and the extrusion moldability was good. This also confirmed that the resin composition was smoothly fed from the hopper to the screw part and melted and mixed well even when melted and stirred in the screw part.

  On the other hand, Comparative Example 1 does not use any inorganic filler when preparing the thermoplastic resin composition, and the mixture of the thermoplastic resin and the liquid additive tends to clog the hopper outlet, and the liquid additive Part of the resin separated and accumulated in the lower part of the hopper, and the extrusion pressure of the resin composition was not constant from the start to the end of extrusion.

  In Comparative Example 2 and Comparative Example 3, the product of the weight average particle size and specific surface area of the inorganic filler used was much less than 10, and the oil absorption was also less than 40 ml / 100 g. Therefore, the liquid additive was not sufficiently absorbed by the inorganic filler. As a result, the surface of the pellet-shaped thermoplastic resin becomes sticky and adheres in the hopper. In Comparative Example 2 and Comparative Example 3, it completely hardens at the hopper outlet, and the resin cannot be fed into the screw part. Met.

  In Comparative Example 4, the inorganic filler used was a product of the weight average particle diameter and the specific surface area specified by the present invention and the condition of oil absorption, but the blending ratio with the liquid additive was 40. : 60, which was outside the range specified in the present invention. As a result, as in Comparative Examples 2 and 3, the surface of the pellet-shaped thermoplastic resin becomes sticky, adheres itself in the hopper, and completely hardens at the hopper outlet, so that the resin cannot be fed into the screw portion. It was possible.

  In Comparative Example 5 and Comparative Example 6, the inorganic filler used was a product of the weight average particle diameter and specific surface area specified by the present invention and the oil absorption amount. The sum total with the additive was 120 parts by weight with respect to 100 parts by weight of the thermoplastic resin. As a result, the resin composition tends to be clogged at the hopper outlet, and a part of the inorganic filler that has absorbed the liquid additive is separated from the thermoplastic resin composition and collected in the lower part of the hopper, and from the start to the end of extrusion molding. The extrusion pressure was not constant.

(Measurement of Young's modulus of extruded products)
Below, the Young's modulus of the extrusion-molded sheet | seat shape | molded using each of Example 6 and Example 7 which is a thermoplastic resin composition of this invention is measured as reference, and the value is shown. First, Example 6 using Hytron, which is a substantially flat porous talc particle, is used as the inorganic filler, and Callite KT, which is a calcium carbonate particle having irregular irregular shapes, is used as the inorganic filler. Example 7 was used to cut the extruded sheet formed into a strip shape having a width of 10 mm and a length of 100 mm to prepare a test piece (hereinafter also referred to as Example 6 test piece and Example 7 test piece). ).

The Young's modulus was measured for the above two test pieces, and the results are shown in Table 3. The Young's modulus was measured in accordance with ASTM D882 by applying stress in each of the sheet extrusion direction and the width direction perpendicular to the extrusion direction, and measuring the Young's modulus in each of the sheet extrusion direction and the width direction.

  In Examples 6 and 7, 100 parts by weight of PE (Petrocene 180) is used as a constituent resin and 12.5 parts by weight of a plasticizer (DOP) is used as a liquid additive. The Young's modulus of the extruded sheet showed different values as shown in Table 3. That is, in both the extrusion direction and the width direction, the Young's modulus of the test piece of Example 7 was low, and the Young's modulus of the test piece of Example 6 showed a high value.

As a factor governing the Young's modulus of the sheet, a plasticizer that is an additive that imparts flexibility to the sheet can be cited as one factor. That is, it is generally considered that the Young's modulus decreases as the amount of plasticizer dispersed in the sheet-constituting resin increases.

Here, the fact that the Young's modulus of the test piece of Example 7 shows a more preferable value than the Young's modulus of the test piece of Example 6 (the effect of adding a plasticizer appears more) is as follows. Was considered. That is, in Example 6, DOP (plasticizer), which is a liquid additive, is adsorbed to porous talc particles, and the liquid additive is adsorbed in the inorganic filler even in a sheet formed using the same. Seems to be maintained to some extent. On the other hand, in Example 7, DOP (plasticizer), which is a liquid additive, is adsorbed on calcium carbonate particles having irregular irregular shapes on the surface. It is inferred that the irregular unevenness present on the surface of the particles is broken by the shear stress of the screw inside and dispersed in the molten resin, so that the plasticizer adsorbed on the particles is also dispersed in the molten resin at the same time. Is done. Therefore, the plasticizer is better dispersed in the test piece of Example 7 than the test piece of Example 6, and the plasticizer exhibits its effect sufficiently in the entire sheet, thereby lowering the Young's modulus, that is, flexibility. It was considered that a certain sheet was formed. Therefore, in the present invention, from the viewpoint of better dispersing the liquid additive once adsorbed on the inorganic filler in the molten resin, and thus in the molded sheet, the inorganic particle surface has an uneven shape. It may be more desirable to use a filler.

It is a graph which shows the correlation of the reciprocal number of the average particle diameter of a calcium carbonate particle, and a surface area.

Explanation of symbols

Black diamond plot The measurement results of spherical general-purpose calcium carbonate having no irregularities on the surface and almost no pores are shown.
Open diamond plot Shows the measurement results of special calcium carbonate.

Claims (2)

A method for producing a thermoplastic resin composition comprising a pellet-shaped thermoplastic resin and a liquid additive,
(A) a pellet-shaped thermoplastic resin;
(B) The weight average particle diameter is 0.1 μm or more and 10 μm or less, the product of the weight average particle diameter (μm) and the specific surface area (m ² / g) is 10 or more, and the boiled linseed oil absorption is 40 ml / 100 g or more. An inorganic filler,
(C) a liquid additive,
With respect to 100 parts by weight of (A), the sum of the parts by weight of (B) and (C) is 15 parts by weight or more and 100 parts by weight or less, and (B) and (C) A thermoplastic resin containing a liquid additive , characterized by having a step of mixing in a mixing device at a blending ratio such that the ratio of parts by weight is (B) / (C) = 1 to 2 A method for producing the composition . The manufacturing method of the thermoplastic resin composition containing the liquid additive of Claim 1 whose said inorganic filler is a calcium carbonate .

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