JP2928839B2 - Manufacturing method for containers with pearl luster - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention is used for, for example, a method for producing a plastic container having a pearly luster, and is particularly used for filling cosmetics, shampoos, rinses, foodstuffs, beverages, pharmaceuticals, detergents, etc., which require an excellent appearance. The present invention relates to a method for producing a container having a pearl luster.

[0002]

2. Description of the Related Art In order to develop a pearl luster, a pearl pigment made of mica or the like is added to a thermoplastic resin, and a pearl luster obtained by melt-molding such a pearl pigment-added resin is exhibited. Containers and the like have been developed.
However, when using such a pearl pigment, there is a method of controlling the appearance only by changing the particle size and the amount of the pearl pigment, and a container having an excellent appearance that is more varied from the aspect of decorativeness. Despite being requested, this has not been answered. Also, pearl pigments have the disadvantage that they are expensive and costly.

On the other hand, there has been proposed a method utilizing a resin composition in which resins which are incompatible with each other are combined. For example, as shown in JP-B-61-39336, a resin composition comprising 10 to 99% by weight of a polyester resin and 1 to 90% by weight of a polyolefin resin, and a thin portion of a container is oriented in at least one direction. Has been proposed.

Further, as disclosed in JP-B-61-24253, a resin mixture comprising 99.5 to 90% by weight of a polyester resin and 0.5 to 10% by weight of a methacrylic resin is obtained by stretch blow molding. Plastic cosmetic bottles have been proposed.

[0005]

However, in the technology utilizing the resin composition in which these mutually incompatible resins are combined as they are, although the surface gloss is very uniform and fine, it is characteristic. Instead of pearly luster, it has no depth, more like a metallic luster, and in the sense of decoration, the impression was too strong and there was a sense of one step.

Further, in this case, in a peeling test using an adhesive tape such as a cellophane tape, remarkable surface peeling occurred, and there was a serious disadvantage that the surface became fluffy. This means that when a label is applied or printed on the surface of the container, not only does it have an adverse effect on the adhesion robustness, but also external factors such as slight rubbing tend to cause significant damage and impair the appearance. Become.

[0007] By the way, a resin composition in which resins that are incompatible with each other are combined has a so-called sea-island structure in its fine structure, and the resin forming the islands is uniformly dispersed in the matrix resin. However, when this is stretch-formed in a uniaxial or biaxial direction, a structure is obtained in which the dispersed phase of the island is elongated in a plate shape together with the matrix phase. For this reason, it is considered that light entering from the outside is reflected multiple times between the matrix phase and the dispersed phase having different refractive indices, and is further transmitted or complicatedly reflected to emit pearl luster.

According to the study of the present inventors, a resin composition combining these incompatible resins is
When stretched in the uniaxial or biaxial direction as it is, the dispersed phase that is elongated in a flat plate shape is evenly distributed near the surface, so the incident light reflects only the light that is multiple-reflected very near the surface. It was speculated that the light that had entered deeply did not return, and that the impression was that there was no depth in the gloss, that is, a glossy luster close to a metallic luster.

Further, if the dispersed phase which is elongated in the form of a flat plate is evenly distributed in the vicinity of the surface, it also has an adverse effect on cellophane tape peeling, and the matrix phase and the dispersed phase have no adhesiveness to each other. It was presumed that it was easy to peel off from the phase boundary near the surface. That is, as a result of intensive research on the problems in the conventional techniques, when obtaining a product exhibiting pearl luster using a resin composition combining resins that are incompatible with each other, the island portion of the sea-island structure is used. By having a unique structure in which the dispersed phase does not exist in the surface portion (or surface layer portion) or its existence is less than in the deep portion, it is very uniform, fine-grained, and deep, It was found that a product having a soft pearly luster and hardly causing surface peeling even in a cellophane tape peeling test was obtained.

The present invention has been made based on the above findings, and an object of the present invention is to produce a container which is very uniform, fine-grained, deep and has a soft pearly luster. Is to provide the law . Another object of the present invention is to provide a method for producing a container in which surface peeling (fuzzing of the surface) hardly occurs even in a cellophane tape peeling test.

[0011]

SUMMARY OF THE INVENTION The object of the present invention is to
Thermoplastic polyester resin having a viscosity of 0.65 to 1.20
A 50 to 99 parts by weight and the thermoplastic polyester resin
Incompatible with A, melt flow rate based on JIS
2. Satisfies the following equation (3) under a load condition of 16 kgf.
Composition containing 50 to 1 part by weight of resin B having a high viscosity
Is used to form a preform by injection molding,
Next, stretch-mold at least 1.1 times in the uniaxial direction
The method for producing a container having a pearl luster
Is achieved. MFR _B <0.001T ² -0.2T + 7 Equation (3) (wherein, MFR _B is put on the resin B load 2.16kgf
Melt flow rate and T are measured based on MFR JIS.
It is a constant temperature and can take values of 190 ° C and 230 ° C. )

That is, according to the above-mentioned production method, a container comprising 50 to 99 parts by weight of a thermoplastic polyester resin A and 50 to 1 part by weight of a resin B incompatible with the thermoplastic polyester resin A is used. Yes, 1 surface layer, 8 inner layers, 1 innermost layer in the thickness direction of the wall of this container.
When the surface layer is divided, the thermoplastic polyester resin A is preferentially present in the surface layer, and the average content of the resin B in the surface layer that is incompatible with the thermoplastic polyester resin A is represented by the following formulas (1) and (2). a container having a pearly luster is obtained) characterized by comprising configured to satisfy
You .

Further, thermoplastic polyester resin A50-9
9 parts by weight and 50 to 1 part by weight of a resin B that is incompatible with the thermoplastic polyester resin A, and is a container formed by stretching at least 1.1 times or more in one axis direction. Although the composition of the wall body is substantially constant in the plane direction, the composition is different in the thickness direction, and the wall body has 1 surface layer, 8 inner layers, and 1 innermost layer in the thickness direction.
When the surface layer is divided, the thermoplastic polyester resin A is preferentially present in the surface layer, and the average content of the resin B in the surface layer that is incompatible with the thermoplastic polyester resin A is represented by the following formulas (1) and (2). a container having a pearly luster is obtained) characterized by comprising configured to satisfy
You .

[0014]

[0015]

0 ≦ B _s / B _c <0.95 Formula (1) B _s <40 Formula (2) B _s : average content of resin B in surface layer (%) B _c : average content of resin B in inner layer rate (%) in the above formula (1) in the present invention and (2), preferably _{0 ≦ B s / B c <} 0.80 B s <30, more preferably 0.1 ≦ B _s / a _{B c <0.70 B s <20} .

That is, by making the design of the resin B in the surface layer and the inner layer as described above, that is, by suppressing the content of the resin B in the surface layer and by giving a concentration gradient to the inner layer, the pearl luster can be reduced. The depth can be increased, and the phenomenon of surface peeling can be suppressed. Then, by designing the structure as in the present invention, the presence of the dispersed phase elongated in the shape of a flat plate near the surface is reduced, and the incident light is not only reflected near the surface but also multiple-reflected to the deep layer. The light is reflected, and the light that has entered the interior is returned, so that the gloss is very deep and soft.

In addition, the fact that the dispersed phase which has been elongated in the form of a flat plate decreases in the vicinity of the surface causes a good result also in the peeling of the cellophane tape, and the interface having no mutual adhesive force decreases in the vicinity of the surface. Is done. The thermoplastic polyester resin A in the invention preferably has a main repeating unit of ethylene terephthalate and an intrinsic viscosity of 0.65 to 1.20. That is,
If the intrinsic viscosity is too small, less than 0.65, the impact resistance of the container tends to be impaired when the container is molded. On the other hand, if the intrinsic viscosity exceeds 1.20 and is too large, molding such as injection blow molding becomes very difficult.

Specifically, for example, polyethylene terephthalate, copolymerized polyester of terephthalic acid, isophthalic acid and ethylene glycol, copolymerized polyester of terephthalic acid, ethylene glycol and 1,4-cyclohexanedimethanol, terephthalic acid and isophthalic acid And ethylene glycol and propylene glycol. These may contain other small amounts of other copolymer components as described below. That is, succinic acid, adipic acid, azelaic acid, sebacic acid, dodecanoic acid, p-
Oxybenzoic acid may also contain diethylene glycol, propylene glycol, butylene glycol, 1,6-hexanediol, neopentyl glycol, polyethylene glycol, polytetramethylene glycol, or the like as a glycol component as a copolymer component.

In the present invention, the resin B which is incompatible with the thermoplastic polyester resin A is a polyolefin resin,
It is selected from the group consisting of a poly (meth) acrylic resin and a polystyrene resin. Specifically, for example, high density polyethylene, low density polyethylene, polypropylene, ethylene-propylene copolymer, ethylene-propylene-butadiene copolymer, ethylene-vinyl acetate copolymer, poly-4-methylpentene, ethylene-methacrylic Acid copolymers and their alkali metal salts, acid-modified polyethylene modified with maleic anhydride, etc., polyolefins such as epoxy-modified polyethylene copolymerized with acid-modified ethylene-vinyl acetate copolymer, glycidyl methacrylate, etc. Resins, lower alkyl (meth) acrylates such as methyl methacrylate, methyl acrylate (hereinafter, these are referred to as methyl (meth) acrylate), ethyl (meth) acrylate, butyl (meth) acrylate, and (meth) acrylonitrile. Lil, these copolymerized copolymer (meth) acrylate of (meth)
Acrylic ester polymers, and styrene-based resins such as polystyrene, impact-resistant polystyrene, and polymethylstyrene are exemplified. These may be used alone,
Further, two or more kinds may be used in combination. Each of them exhibits pearl luster when combined with the thermoplastic resin A, but polyethylene, polypropylene, ethylene-vinyl acetate copolymer, and methyl methacrylate are preferred.

The container having the structure as described above according to the present invention is obtained, for example, by the following method. As a first method, a thermoplastic polyester resin A having an intrinsic viscosity of 0.65 to 1.20 as described above is used, and a resin B incompatible with the thermoplastic polyester resin A is JIS.
By using the resin B having a viscosity satisfying the following formula (3) under a load condition of a melt flow rate of 2.16 kgf based on the above, a container having a resin composition distribution as in the present invention can be obtained.

[0022] MFR _B <0.001T ² -0.2T + 7 Equation (3) where, MFR _B is a melt flow rate at a load 2.16kgf resin B, T is the measured temperature based on JIS the MFR _B (JIS-K7210) 190 ° C., 23
It can take the value of 0 ° C. The value of T is 190 ° C. for a polyethylene resin or an ethylene-vinyl acetate copolymer, and 230 ° C. for a polypropylene resin, a (meth) acrylic resin and a styrene resin.

[0023] wherein in Formula (3), the melt viscosity of the resin B it is indicative that selectively use considerably higher than the resin of the conventional injection grade, specifically MFR _B at 190 ° C. about 5 or less, it takes a value that MFR _B is about 14 or less at 230 ° C.. Incidentally, preferably also within the scope of formula (3), it is preferable to select a resin to assume a lowest possible value MFR _B. That is, more preferably ^{_{MFR B <1/2 (0.001T 2 -0.2T}} + 7).

In this manner, the thermoplastic polyester resin A and the resin B incompatible with the thermoplastic polyester resin A are selected, and the weight ratio of each resin A / B is 50-99 / 1-5.
0, preferably 70-95 / 5-30, more preferably 80-90 / 10-20, and blending using a twin-screw kneader or the like. The obtained mixed resin composition is, for example, injected. When the stretch molding is performed by a stretch blow molding machine such as a blow molding machine, a container having the structure of the present invention can be obtained.

The stretch blow molding machine may be either an injection blow molding machine of a hot parison method or an injection blow molding machine of a cold parison method, and has an effect of stretching the thermoplastic polyester resin A during molding. What is necessary is just to stretch 1 time or more. When a resin B having a considerably higher melt viscosity than that of a normal injection grade resin is selected, in the injection blow molding method, the resin B is preferentially placed in the center of the preform wall in the injection molding step of the preform. On the other hand, a thermoplastic polyester resin A having a sea-island structure having a composition distribution of being distributed on the preform surface is formed. As a result, after the stretching blow step, the sea-island structure is stretched as it is, and a container having a specific distribution structure in the thickness direction of the wall surface is obtained. The same applies to extrusion stretch blow molding.

[0026]

[0027]

The material having the specific structure as described above has a very uniform surface gloss, a fine texture, and a deep, soft pearly luster. . Further, in an adhesive peel test of a cellophane tape or the like, the surface is hardly peeled off, and has a satisfactory appearance and performance as a container. In addition, the container of the present invention obtained in this manner is a moisture lotion,
Various skin lotions such as massage lotion, skin lotion, cleansing lotion, emollient lotion, baby oil, skin creams such as under makeup cream, burnishing cream, emollient cream, various face care such as liquid foundation, etc.
Hair care products such as skin care, body care, makeup cosmetics, shampoo, rinse, hair conditioner, permablowing agent, hair color, etc. It is suitable as a container for filling things that generally require an excellent appearance such as glass cleaners, bleaching agents, softeners, pastes, dishwashing detergents, cleansers, various household detergents, and other foodstuffs and pharmaceuticals.

[0029]

The present invention will be specifically described below with reference to examples.
The present invention is not limited only to these examples. [Example 1] Polyethylene terephthalate having an intrinsic viscosity of 0.77 [Mitsui PET J125, Mitsui Pet Resin Co., Ltd.]
Was dried with hot air at 120 ° C. overnight and a test temperature of 2
JIS K-721 at 30 ° C, test load 2.16kgf
The melt flow index obtained based on 0 is 0.5
(G / 10 min) polypropylene (Hypol B230, manufactured by Mitsui Petrochemical Industries, Ltd.) in a weight ratio of 9%.
The mixture was mixed at a ratio of 0:10, and the mixture was biaxially kneaded at a resin temperature of 280 ° C. (using a PCM45II-30 extruder of φ45 mm manufactured by Ikegai Iron Works Co., Ltd.), extruded into strands, cooled, and then cooled. To obtain pellets. The pellets were dried with hot air at 120 ° C. overnight,
The resin temperature was 290 ° C. and the injection pressure was 45 kg / cm ^{2 using an} axial stretch blow molding machine (a biaxial stretch blow molding machine manufactured by Nissei ASB).
To give a test tubular preform. Next, the preform is temperature-controlled at about 110 ° C. (hereinafter referred to as a stretching temperature) at a preheating station of the molding machine, and further, a blow pressure of 20 kg / cm ² at a blow station.
Compressed air was blown into the preform at a pressure of 4 to obtain a cylindrical bottle exhibiting a pearl luster of the present invention having a surface magnification of 4.5, a bottle weight of 32 g, and a capacity of 300 ml.

After cutting the body of this bottle and cutting out the cross section of the container wall with a microtome, the product was manufactured by Hitachi, Ltd.
As a result of observing with a -7000 type transmission electron microscope and analyzing the image, the surface layer and the innermost layer (each thickness is 1% of the total thickness)
%), 5% polypropylene in area ratio was confirmed. This B _s in the formula (1) and (2) the expression is 3.3wt%, B _s / B _c is 0.29.

Then, a cellophane tape was closely adhered to the bottle in the longitudinal direction, and immediately peeled off under a constant load. Then, the surface condition of the bottle to which the cellophane tape adhered was observed (hereinafter, this is referred to as the surface). Peeling test). As a result, peeling of the surface layer was observed in a part of the bottle,
The amount was very small. [Comparative Example 1] Polyethylene terephthalate having an intrinsic viscosity of 0.77 [Mitsui PET J125, Mitsui Pet Resin Co., Ltd.]
Was dried with hot air at 120 ° C. overnight and a test temperature of 2
JIS K-721 at 30 ° C, test load 2.16kgf
The melt flow index obtained based on 0 is 20
(G / 10 min) polypropylene (Hypol J858Y, manufactured by Mitsui Petrochemical Industry Co., Ltd.) at a weight ratio of 90:10 and melt-kneaded in the same manner as in Example 1 to obtain pellets. Is similarly biaxially stretched and blow-molded, the area ratio is 4.5 times, the bottle weight is 32 g, and the capacity is 300 m.
1 gave a cylindrical bottle exhibiting a metallic pearl luster.

The cross section of the body wall of this bottle was similarly observed with a transmission electron microscope and image analysis revealed that the surface ratio of the surface layer and the innermost layer (each thickness was 10% of the total thickness) was 16% in area ratio. Polypropylene was identified. This is B _s is 1
In 1wt%, B _s / B _c is 1.1. Then, as a result of the surface peeling test of this bottle, the adhered surface of the cellophane tape was peeled off with fuzzing over the front surface.

Comparative Example 2 The same polyethylene terephthalate and polypropylene as in Example 1 were used in a weight ratio of 40:
The pellets obtained by mixing and melting and kneading at a ratio of 60 were similarly biaxially stretched and blow-molded.
A cylindrical bottle poor in pearl luster having a bottle weight of 32 g and a capacity of 300 ml was obtained.

The cross section of the body wall of this bottle was similarly observed with a transmission electron microscope, and image analysis showed that the surface ratio of the surface layer and the innermost layer (each thickness was 10% of the total thickness) was 61% in area ratio. Polypropylene was identified. This is B _s 5
In 0.4wt%, B _s / B _c is 0.84. Then, as a result of the surface peeling test of this bottle, the adhered surface of the cellophane tape was peeled off with fuzzing over the front surface.

Example 2 A polyethylene terephthalate having an intrinsic viscosity of 0.77 (Mitsui PET J125, manufactured by Mitsui Pet Resin Co., Ltd.) was dried with hot air at 120 ° C. overnight, at a test temperature of 190 ° C. and a test load of 2. JI at 16kgf
A low-density polyethylene (Mirason 50, manufactured by Mitsui Petrochemical Industries, Ltd.) having a melt flow index determined based on SK-7210 of 1.9 (g / 10 min) in a weight ratio of 90:10. And pellets obtained by melt-kneading in the same manner as in Example 1 were similarly biaxially stretched and blow-molded to obtain a 4.5 times area ratio, a bottle weight of 32 g,
A cylindrical bottle having a pearly luster of the present invention having a capacity of 300 ml was obtained.

The cross section of the body wall of this bottle was similarly observed with a transmission electron microscope, and image analysis revealed that the surface ratio was 6.7 in the surface layer and the innermost layer (each thickness was 10% of the total thickness). % Low density polyethylene was identified. This is B
_s is at 4.5wt%, B _s / B _c is 0.42. As a result of the surface peeling test of this bottle, peeling of the surface layer was observed in a part of the bottle, but the amount was extremely small.

Example 3 Polyethylene terephthalate (Mitsui PET J125, manufactured by Mitsui Pet Resin Co., Ltd.) having an intrinsic viscosity of 0.77 was dried with hot air at 120 ° C. overnight, at a test temperature of 190 ° C. and a test load of 2. JI at 16kgf
A low-density polyethylene (Milason 53, manufactured by Mitsui Petrochemical Industries, Ltd.) having a melt flow index of 3.3 (g / 10 min) determined based on SK-7210 in a weight ratio of 90:10. And pellets obtained by melt-kneading in the same manner as in Example 1 were similarly biaxially stretched and blow-molded to obtain a 4.5 times area ratio, a bottle weight of 32 g,
A cylindrical bottle having a pearly luster of the present invention having a capacity of 300 ml was obtained.

The cross section of the body wall of this bottle was similarly observed with a transmission electron microscope and image analysis revealed that the area ratio of the surface layer and the innermost layer (each thickness was 10% of the total thickness) was 7%. Low density polyethylene was identified. This B _s is at 4.7wt%, B _s / B _c is 0.45. As a result of the surface peeling test of this bottle, peeling of the surface layer was observed in a part of the bottle, but the amount was extremely small.

Comparative Example 3 Polyethylene terephthalate having an intrinsic viscosity of 0.77 (Mitsui PET J125, manufactured by Mitsui Pet Resin Co., Ltd.) was dried with hot air at 120 ° C. overnight, at a test temperature of 190 ° C. and a test load of 2. JI at 16kgf
The melt flow index determined based on SK-7210 is 23 (g / 10 min) and low-density polyethylene [Mirason 68, manufactured by Mitsui Petrochemical Industries, Ltd.] is adjusted to have a weight ratio of 90:10. And melt-kneaded in the same manner as in Example 1. The pellets obtained were biaxially stretched and blow-molded in the same manner to obtain a cylindrical bottle exhibiting a pearl luster having an area magnification of 4.5, a bottle weight of 32 g, and a capacity of 300 ml. .

The cross section of the body wall of this bottle was similarly observed with a transmission electron microscope, and image analysis revealed that the surface layer and the innermost layer (each thickness was 10% of the total thickness) had an area ratio of 18%. Low density polyethylene was identified. This is B _s
There at 12.6wt%, B _s / B _c is 1.3. Then, as a result of the surface peeling test of this bottle, the adhered surface of the cellophane tape was peeled off with fuzzing over the front surface.

Example 4 Polyethylene terephthalate (Mitsui PET J125, manufactured by Mitsui Pet Resin Co., Ltd.) having an intrinsic viscosity of 0.77 was dried with hot air at 120 ° C. overnight, at a test temperature of 230 ° C. and a test load of 2. JI at 16kgf
Polymethyl methacrylate having a melt flow index of 6.5 (g / 10 min) based on SK-7210 [Delvet 560F, Asahi Kasei Corporation
And a pellet obtained by melt-kneading in the same manner as in Example 1 and biaxially stretch-blown in the same manner as in Example 1. A cylindrical bottle having a pearly luster of the present invention and weighing 32 g and having a capacity of 300 ml was obtained.

The cross section of the body wall of this bottle was similarly observed with a transmission electron microscope and image analysis revealed that the surface layer and the innermost layer (each thickness was 10% of the total thickness) had an area ratio of 9.5. % Low density polyethylene was identified. This is B
_s is at 8.2wt%, B _s / B _c is 0.79. As a result of the surface peeling test of this bottle, peeling of the surface layer was observed in a part of the bottle, but the amount was extremely small.

[0043]

[0044]

[0045]

[0046]

According to the present invention, a very uniform, fine-grained, deep and soft pearly luster is exhibited,
Furthermore, for example, a material that hardly causes surface peeling even in a cellophane tape peeling test can be obtained.

──────────────────────────────────────────────────の Continuation of the front page (51) Int.Cl. ⁶ Identification code FI C08L 67:02 (56) References JP-A-2-187450 (JP, A) JP-A-60-76325 (JP, A)

Claims (1)

(57) [Claims] 1. 50 to 99 parts by weight of a thermoplastic polyester resin A having an intrinsic viscosity of 0.65 to 1.20, which is incompatible with the thermoplastic polyester resin A, and has a melt flow rate based on JIS of 2.16 kgf. A resin composition containing 50 to 1 part by weight of a resin B having a viscosity satisfying the following formula (3) under the load condition of is used, a preform is formed by injection molding, and then a preform is formed in at least one axis direction.
A method for producing a container having a pearly luster, characterized in that the container is stretch-formed at least twice. MFR _B <0.001T ² −0.2T + 7 Equation (3) where MFR _B is a melt flow rate of the resin B at a load of 2.16 kgf, T is a measurement temperature based on JIS of the MFR _B , 190 ° C., 230 ° C. Can be taken.