JP2001206956A - Thermoplastic resin molded product - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a thermoplastic resin molded product where conflicting properties such as a soft touch, matting or a lustrous feeling with depth coexist. SOLUTION: This thermoplastic resin molded product 1 is made of two or more kinds of thermoplastic resins A and B incompatible with each other and capable of forming a continuous phase and dispersed phases when being blended, and also has a structure where respective kinds of resins A and B existing in the continuous and central phases are reversed at least once between the surface layer 2 and the central layer 3 of the molded product in such a way as to make conflicting properties coexist at a high level.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermoplastic resin molded article used in home electric appliances, automobiles, houses, and the like.

[0002]

2. Description of the Related Art Conventionally, thermoplastic resin molded articles having a complicated shape by injection molding, extrusion molding, vacuum molding and the like can be obtained relatively easily and with high efficiency.
It is widely used as a member in the housing field. Since these members have different required physical properties depending on their use, various thermoplastic resins are used singly or in combination according to each use.

[0003] In recent years, the quality required in the above-mentioned fields has been diversified, and it has become necessary to achieve high-dimensional compatibility of physical properties that have been conventionally considered to be contradictory. For example, automobile interior materials have high rigidity and soft touch feeling, home electric appliances have matte product surfaces, and automobile and housing members have depth glossiness.

[0004] Since it is difficult to achieve both of these physical properties with a single thermoplastic resin, two or more materials are used in combination. However, it cannot be said that the opposite physical properties are compatible at a high level. . Also, multilayer formation, coating and lamination, etc. are being studied from the viewpoint of molding methods, but at present, they cannot completely meet the high required levels.

[0005] For example, as an example of realizing heat resistance and soft feeling by using two kinds of resins, see Japanese Patent Publication No. 2653512.
Publication. However, in the invention described in this publication, since two kinds of resins are blended, only the average value of both resins is given in rigidity and soft feeling, and the intended function is completely achieved. It's hard to say I'm satisfied.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of such a situation, and an object of the present invention is to achieve a balance between contradictory physical properties such as soft touch feeling, matte or depth glossiness. To provide a molded thermoplastic resin article.

[0007]

The thermoplastic resin molded article of the present invention is a molded article comprising a combination of two or more incompatible thermoplastic resins capable of forming a continuous phase and a dispersed phase when blended. As illustrated in FIG. 2, the resin type (A, B) of the continuous phase and the dispersed phase is inverted at least once between the molded article surface layer 2 and the molded article center layer 3. Attached.

[0008] In the thermoplastic resin molded article of the present invention, an immiscible 2 which can form a continuous phase and a dispersed phase when blended.
As the thermoplastic resin of more than one kind, for example, two kinds of thermoplastic resin A having high rigidity and thermoplastic resin B having high flexibility are used, and as shown in FIG. If the molding surface layer 2 has a structure in which the continuous phase is formed of the thermoplastic resin B, a molded article having a low rigidity on the surface and a soft touch feeling can be obtained while the entire molded article has rigidity. In addition, the combination of the opaque resin and the transparent resin has other advantages such as depth glossiness and matting of the color tone.

The thickness and shape of the thermoplastic resin molded article of the present invention are not particularly limited. However, extremely thick ones are difficult to cool down to the central layer of the molded article. Absent.

In the above description, a specific example in which two types of incompatible thermoplastic resins are used has been described. However, the present invention is not limited to this, and the thermoplastic resin molded article of the present invention It may be a molded article in which three or more types of incompatible thermoplastic resins capable of forming a continuous phase and a dispersed phase when combined are used.

The details of the thermoplastic resin molded article of the present invention will be described below.

The thermoplastic resin used in the thermoplastic resin molded article of the present invention is not particularly limited as long as it is a combination of two or more resins capable of forming a continuous phase and a dispersed phase when blended. For example, olefin resin, styrene resin, ABS resin, ethylene-vinyl acetate copolymer, acetal resin, polyamide resin, polyimide resin, amide imide resin, acrylic resin, polyester resin, polycarbonate resin, polyphenylene oxide, noryl (polystyrene-modified polyphenylene oxide) Any thermoplastic resin selected from two or more thermoplastic urethanes, thermoplastic elastomers (olefin-based, styrene-based, urethane-based) and the like may be used.

[0013] In the thermoplastic resin molded article of the present invention, a compatibilizer may be appropriately used for finely dispersing two or more incompatible resins and for interfacial adhesion between the resins. The type of the compatibilizer depends on the combination of the resins selected from the thermoplastic resin group described above. Examples thereof include maleic acid-modified polyolefin, acrylic acid-modified polyolefin, and epoxy group-containing resin. The amount of the compatibilizer is
Although it depends on the mixing ratio of two or more kinds of thermoplastic resins, it is preferably about 1 to 10 parts by weight based on 100 parts by weight of two or more kinds of thermoplastic resins. When the amount is less than 1 part by weight, the resin is not finely dispersed, and when the amount exceeds 10 parts by weight, the rigidity of the thermoplastic resin molded article is reduced.

The melt viscosity of the thermoplastic resin is an important point for achieving the object of the present invention. For example, when two types of thermoplastic resins are selected, the temperature-viscosity curve has one point in the molding temperature range. Need to intersect at That is, assuming that two types of thermoplastic resins are A and B, the resin A has a higher viscosity at a certain temperature or higher in the molding temperature range, whereas the resin B has a higher viscosity at a certain temperature or lower. It is necessary.

As described above, the temperature-viscosity curves of the two types of resins intersect at one point in the molding temperature range, so that at least one continuous phase and one dispersed phase are formed between the molded article surface layer and the molded article central layer. The times will be reversed. This is due to the following mechanism.

First, when two types of resins are blended, factors that determine which is a continuous phase (sea) and which is a dispersed phase (island) are roughly divided into a volume ratio and a melt viscosity ratio. When the volume ratio is in the range of 80:20 to 20:80, the probability that the low-viscosity resin of the two kinds of resins becomes a continuous phase, otherwise, the side with the higher volume fraction becomes the continuous phase Is high.

Using this principle, two types of resins A,
A region where the temperature and viscosity of the melt-kneaded mixture at the temperature where the temperature-viscosity curve of B intersects and the temperature of which is adjusted to the temperature at which it intersects or below (die).
, The blend of the two resins is rapidly cooled in the vicinity of the temperature-controlled region, that is, in the molded article surface layer, and the melt viscosities of A and B are reversed, so that the continuous phase and the dispersed phase are reversed. Conversely, the blend is gradually cooled in a portion away from the temperature-controlled region (mold), that is, in the center layer of the molded product, so that the blend solidifies before the continuous phase and the dispersed phase are reversed. As a result, the continuous phase and the dispersed phase are inverted between the surface layer and the central layer of the thermoplastic resin molded article. Note that the viscosity ratio of the two types of resin is locally different depending on the temperature distribution of the resin, and the shear stress acting on the two types of resin has a distribution depending on the shape of the flow path. Between the continuous phase and the dispersed phase may be inverted two or more times.

The method of blending two (or three or more) thermoplastic resins is not particularly limited, but a kneading extruder, roll kneading, or plast mill or the like is used to finely disperse the dispersed phase with high kneading. Good. The temperature at the time of melt-kneading needs to be equal to or higher than the temperature at the point where the temperature-viscosity curves of the two (or three or more) thermoplastic resins intersect. If it is less than that, no reversal of the continuous phase and the dispersed phase occurs in the molded article.

Further, as a method of molding into a thermoplastic resin molded product after blending, the molten blend is used for 2 hours.
It is preferable to use a method of passing through a zone (mold) whose temperature is controlled to be equal to or lower than the temperature at which the temperature-viscosity curves of the types (or three or more types) of thermoplastic resins intersect. More preferably, from the viewpoint of moldability, a method in which the resin is passed through a zone (mold) whose temperature is controlled to be equal to or lower than the melting temperature of the resin to be used. Specific molding methods include injection molding, extrusion molding, inflation molding, and hollow molding.

The appearance of the difference between the continuous phase and the dispersed phase of the thermoplastic resin molded article between the surface layer of the molded article and the central layer of the molded article is explained by a transmission electron microscope (TEM) or a field emission scanning electron microscope (FE- It can be confirmed by observation with SEM). Specifically, by dyeing the fracture surface of the thermoplastic resin molded article with an oxidizing agent such as osmium tetroxide, one of the continuous phase or the dispersed phase is observed to be dark, so the sea-island structure is reversed. You can observe that.

In the thermoplastic resin molded article of the present invention, the volume fraction of two or more incompatible thermoplastic resins capable of forming a continuous phase and a dispersed phase differs between the molded article surface layer and the molded article central layer. It is preferable to do so.

In the molded article surface layer and the molded article central layer, 2
In order to change the volume fraction of more than one type of thermoplastic resin, an extreme difference may be made in the melt viscosity at the molding temperature of the thermoplastic resin used. By making an extreme difference, more resin having a low melt viscosity collects in a portion where a shear stress is applied near the cooling zone (mold). This is because a low-viscosity resin is more advantageous in a portion to which a shear stress is applied in order to reduce a frictional force.

The difference in melt viscosity between the two or more thermoplastic resins at the molding temperature is preferably from 1,000 to 5,000 poise. If the difference in melt viscosity is smaller than 1000 poise, there is no difference in the volume fraction, and if it is larger than 5000 poise, the degree of kneading of two or more thermoplastic resins becomes poor, and the effect of the present invention cannot be sufficiently exhibited.

In the thermoplastic resin molded article of the present invention, 2
When various types of incompatible thermoplastic resins are used, the mixing ratio (wt%) is preferably in the range of 80:20 to 20:80. By setting the mixing ratio of the two types of thermoplastic resins in such a range, the conversion between the continuous phase and the dispersed phase between the surface layer and the central layer of the thermoplastic resin molded product can be more stably caused. Will be possible. That is, since the temperature range in which molding can be performed is widened and a high shear rate is not required, there is no need to use a cooling zone (die) having a special structure, so that molding can be easily performed. In addition, with regard to the physical properties of the obtained thermoplastic resin molded product, it is possible to make the opposite properties compatible at a high level.

In the thermoplastic resin molded article of the present invention, 2
It is preferable that the difference between the solubility parameters of at least one kind of incompatible thermoplastic resin is 0.3 or more apart. The reason will be described below with reference to an example in which two types of thermoplastic resins are used.

First, in the thermoplastic resin of the present invention, a continuous phase and a dispersed phase are clearly present, and each preferably has a unique role (rigidity, flexibility, transparency, etc.). When blending different kinds of thermoplastic resins, a clear phase separation is required. When two types of thermoplastic resins are blended, whether they are completely mixed or phase-separated depends on the difference between the solubility parameters of the two types of resins.

Here, the solubility parameter (σ) is defined as σ
= ΡΣFi / M. However,
ρ is the density of the thermoplastic resin, M is the molecular weight of the monomer constituting the thermoplastic resin, and Fi is the molar attraction constant of the monomer group, which is an individually determined value. And
If the solubility parameter is large, the compatibility is low and the mixture is difficult to mix. If the difference is small, the compatibility is high and the mixture is easy to mix.
If it is less than 3, it becomes difficult to distinguish between the continuous phase and the dispersed phase. Thus, in order to sufficiently exhibit the effects of the present invention, the difference between the solubility parameters of the two incompatible thermoplastic resins needs to be separated by 0.3 or more.

In the thermoplastic resin molded article of the present invention, it is preferable to use two or more incompatible thermoplastic resins having a difference in flexural modulus of 1.5 Pa or more. When the difference between the bending elastic moduli of two or more resins is 1.5 Pa or more, it is possible to obtain a molded article having both rigidity and flexibility. Here, a resin having a high flexural modulus is generally hard to bend and has heat resistance, and thus maintains rigidity even at a high temperature, whereas a resin having a low flexural modulus easily bends and has flexibility. Therefore, by combining a high-rigidity resin with a bending elastic modulus of 1.5 GPa or more and a soft resin, it is possible to achieve both high rigidity and a soft touch feeling.

In the thermoplastic resin molded article of the present invention, 2
More than one type of incompatible thermoplastic resin, Noryl, ABS,
When a combination of one kind of resin selected from the group of polyamide and one kind of resin selected from the group of polyolefin, thermoplastic elastomer, polycarbonate, and acrylic resin, particularly, heat resistance (rigidity) and flexibility are obtained. At a high level.

That is, resins of the group consisting of Noryl, ABS, and polyamide are generally resins having high heat resistance,
Polyolefins, thermoplastic elastomers, polycarbonates, and acrylic resins are resins with high flexibility or transparency, so combining resins selected from these two groups can achieve both high rigidity and soft touch feeling and high rigidity. And the glossiness of colors can be achieved at the same time. <Function> According to the thermoplastic resin molded article of the present invention, in a molded article comprising a combination of two or more incompatible thermoplastic resins capable of forming a continuous phase and a dispersed phase when blended,
At least once between the surface layer and the central layer, the continuous phase (sea portion of the sea-island structure) and the dispersed phase (island portion of the sea-island structure) have a reversed structure. Combinations make it possible to balance conflicting physical properties.

In the thermoplastic resin molded article of the present invention, 2
By giving a difference in melt viscosity during molding of more than one type of thermoplastic resin, it is possible to change the volume fraction of two components (or three or more components) between the molded product surface layer and the molded product intermediate layer. Become.

In the thermoplastic resin molded article of the present invention, for example, when two types of thermoplastic resins are used and the mixing ratio of the two types of thermoplastic resins is 80:20 to 20:80,
It becomes possible to sufficiently draw out the respective roles of the continuous phase and the dispersed phase in the molded article.

When the difference between the solubility parameters of the two or more thermoplastic resins is 0.3 or more, phase separation occurs reliably, so that the continuous phase and the separated phase are clearly distinguished. It is possible to achieve the purpose sufficiently. further,
1.5G difference in flexural modulus between two or more thermoplastic resins
When it is Pa or more, a combination of a highly rigid resin and a flexible resin is obtained, and it is possible to achieve both high rigidity and flexibility at a high level.

In the thermoplastic resin molded article of the present invention, 2
More than one type of incompatible thermoplastic resin, for example, Noryl,
When the combination of one kind of resin selected from the group of ABS and polyamide and one kind of resin selected from the group of polyolefin, thermoplastic elastomer, polycarbonate and acrylic resin, the intended object of the present invention is as follows. It is possible to achieve this sufficiently.

[0035]

EXAMPLES Examples of the present invention will be described below together with comparative examples. <Example 1> Noryl resin (manufactured by GE Plastics, trade name: GTX600, density: 1.10 g / cm ³ ) and olefin-based thermoplastic elastomer (manufactured by Sumitomo Chemical Co., trade name: TPE3572, density: 0.88 g / cm ³ ) ³ , MFR
= 15 g / 10 min) in the ratio shown in Table 1 below, and a twin-screw kneading extruder (trade name: PCM, manufactured by Ikegai Kiko Co., Ltd.)
-30) at a barrel temperature of 260 ° C.
After being extruded from a strand die having a diameter of 3 mm adjusted to a temperature of 0 ° C., it was cooled with water and pelletized to a length of 3 mm with a pelletizer.

After drying the pellets, an in-line injection molding machine (AUTOSHOT MODE, manufactured by FANUC) is used.
L75), melt-kneaded at a barrel temperature of 260 ° C., and injection-molded using a mold temperature-controlled to 20 ° C. to obtain a rectangular parallelepiped thermoplastic resin molded product 1 having the shape and dimensions shown in FIG. I got

A fracture surface (see FIG. 1) of the obtained thermoplastic resin molded product was subjected to a field emission scanning electron microscope (FE-SE).
Observed in M), near the surface of the molded article, the olefin-based thermoplastic elastomer was a continuous phase, whereas in the center layer of the molded article 1.5 mm from the surface, the noryl resin was in a continuous phase. It was confirmed that the continuous phase and the dispersed phase were inverted around 0.5 mm from the product surface.

The volume fraction of the continuous phase and the dispersed phase near the surface of the thermoplastic resin molded article obtained in Example 1 and the volume fraction of the continuous phase and the dispersed phase near the center of the molded article were determined by FE. -Calculated by applying an SEM photograph to an image processing apparatus. The results are shown in Table 2 below.

Further, a sample was cut out of the thermoplastic resin molded article, and a bending test was performed in accordance with JIS K 7171 to measure a bending elastic modulus, and a compression test was performed in accordance with JIS K 7181 to measure a compression elastic modulus. The results are shown in Table 2 below.

As an evaluation of the obtained thermoplastic resin molded product, total light transmittance was measured according to ASTM D-1003. The results are shown in Table 2 below. <Example 2> Instead of the olefin-based thermoplastic elastomer, a styrene-based thermoplastic elastomer (manufactured by Kuraray Co., Ltd., trade name: Septon 2063, density 0.89 g / cm ³ , M
Example 1 except that FR = 22 g / 10 min) was used.
In the same manner as above, a rectangular parallelepiped thermoplastic resin molded product was obtained.

With respect to the obtained thermoplastic resin molded product, the volume fraction of the continuous phase and the dispersed phase, the flexural modulus / compressive modulus, and the total light transmittance were measured in the same manner as in Example 1. The results are shown in Table 2 below. Example 3 Except that the blend of the noryl resin and the olefin-based thermoplastic elastomer was set to the ratio shown in Table 1,
A rectangular parallelepiped thermoplastic resin molded product was obtained in the same manner as in Example 1.

With respect to the obtained thermoplastic resin molded product, the volume fraction of the continuous phase and the dispersed phase, the flexural modulus / compressive modulus, and the total light transmittance were measured in the same manner as in Example 1. The results are shown in Table 2 below. <Example 4> As a combination of thermoplastic resins, nylon 66 (trade name: 2026B, manufactured by Ube Industries, density: 1.14)
g / cm ³ ) and polypropylene (manufactured by Mitsubishi Chemical Corporation, trade name: MA03, density 0.90 g / cm ³ , MFR = 25)
g / 10 min), except that a rectangular parallelepiped thermoplastic resin molded product was obtained in the same manner as in Example 1. About the obtained thermoplastic resin molded article, it carried out similarly to Example 1,
The volume fraction, flexural modulus / compressive modulus, and total light transmittance of the continuous phase and the dispersed phase were measured. The results are shown in Table 2 below. <Example 5> ABS was used as a combination of thermoplastic resins.
Resin (made by Asahi Kasei Corporation: Styrac ABS20)
0, density 1.05 g / cm ³ , MFR = 12.5 g / 1
0 minutes) and an acrylic resin (trade name: Acrypet IR D-50, manufactured by Mitsubishi Chemical Corporation, density: 1.16 g / cm ³ , MF
Example 1 except that R = 7.6 g / 10 min) was used.
In the same manner as above, a rectangular parallelepiped thermoplastic resin molded product was obtained.

With respect to the obtained thermoplastic resin molded product, the volume fraction of the continuous phase and the dispersed phase, the flexural modulus / compressive modulus, and the total light transmittance were measured in the same manner as in Example 1. The results are shown in Table 2 below. <Comparative Example 1> The same procedure as in Example 1 was performed except that a rectangular parallelepiped thermoplastic resin molded product was obtained using 100% of the noril resin.

With respect to the obtained thermoplastic resin molded product, the volume fraction of the continuous phase and the dispersed phase, the flexural modulus / compressive modulus, and the total light transmittance were measured in the same manner as in Example 1. The results are shown in Table 2 below. <Comparative Example 2> Olefin-based thermoplastic elastomer 100
% Was used, except that a rectangular parallelepiped thermoplastic resin molded product was obtained using%.

With respect to the obtained thermoplastic resin molded product, the volume fraction of the continuous phase and the dispersed phase, the flexural modulus / compressive modulus, and the total light transmittance were measured in the same manner as in Example 1. The results are shown in Table 2 below.

[0046]

[Table 1]

[0047]

[Table 2]

[0048]

As described above, the thermoplastic resin molded article of the present invention comprises a combination of two or more incompatible thermoplastic resins capable of forming a continuous phase and a dispersed phase when blended. Since the resin type of the continuous phase and the dispersed phase is inverted at least once between the surface layer of the molded article and the central layer of the molded article, it is possible to achieve the opposite properties at a high level. This makes it possible to realize a thermoplastic resin molded product having physical properties that could not be achieved with a conventional single resin, for example, rigidity and flexibility, rigidity and glossiness of color, and the like.

[Brief description of the drawings]

FIG. 1 is an overall perspective view of an embodiment of a thermoplastic resin molded product of the present invention.

FIG. 2 is a view schematically showing the structure of a thermoplastic resin molded product of the present invention.

[Explanation of symbols]

 1 Thermoplastic resin molded product 2 Molded product surface layer 3 Molded product central layer

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Claims (6)

[Claims] 1. A molded article comprising a combination of two or more incompatible thermoplastic resins capable of forming a continuous phase and a dispersed phase when blended, comprising a molded article surface layer and a molded article central layer. Between the continuous phase and the dispersed phase,
A thermoplastic resin molded product characterized by being inverted. 2. The molded article surface layer and the molded article center layer have different volume fractions of two or more types of incompatible thermoplastic resins capable of forming a continuous phase and a dispersed phase. The thermoplastic resin molded article according to the above. 3. The mixing ratio of an incompatible thermoplastic resin capable of forming a continuous phase and a dispersed phase when blended is from 80:20.
The thermoplastic resin molded product according to claim 1, wherein the ratio is in the range of 20:80. 4. The thermoplastic resin molded article according to claim 1, wherein two or more incompatible thermoplastic resins having a difference in solubility parameter of 0.3 or more are used. 5. The thermoplastic resin molded article according to claim 1, wherein two or more types of incompatible thermoplastic resins having a difference in flexural modulus of 1.5 GPa or more are used. 6. The one or more incompatible thermoplastic resins capable of forming a continuous phase and a dispersed phase when blended are selected from the group consisting of Noryl (registered trademark), ABS, and polyamide. The thermoplastic resin molded product according to claim 1, wherein the resin is a combination of a resin and one resin selected from the group consisting of a polyolefin, a thermoplastic elastomer, a polycarbonate, and an acrylic resin.