JP4655602B2 - Method for producing black matte-like stretched container - Google Patents

Description

  The present invention relates to a method for producing a stretched container made of polyethylene terephthalate resin using a black colorant and requiring a matte tone (matte tone) and a drop strength.

  In such a container, when a polyethylene terephthalate resin is used as a raw material, gloss is inevitably left, so that it is difficult to obtain a matte feeling, and it is impossible to achieve with normal molding conditions and pigments.

As an existing technique, there is a method in which a preform at the time of stretching is stretched with a crystallized (whitening) appearance. In addition, as another technique, there are a method of mixing a pigment that looks like a matte tone, and a method of dispersing and mixing fine powder particles.
JP 11-348105 A

  However, among the above-described conventional techniques, the former stretching method (hereinafter, simply referred to as a pre-molded body in the present invention) is performed with a crystallized (whitening) appearance, and the dropping strength is weak (easy to break). The surface is easy to peel off. In addition, the latter method of mixing a pigment that looks like a matte tone or dispersing and mixing fine particles is that the surface of the polyethylene terephthalate resin remains glossy even if stretched, and the matte feeling cannot be achieved by any means. (It will be pearly, not matte). In particular, in the method of dispersing and mixing fine powder particles, voids are generated around the fine powder particles when stretched, which is a major factor in causing separation.

The present inventors have made various studies in order to solve the problems of these conventional methods.
That is, as a result of searching various conditions such as the intrinsic viscosity of polyethylene terephthalate resin to be employed, improvement of molding process, pigment and dispersant, draw ratio, etc., it is made of polyethylene terephthalate resin using a black colorant and has a matte feeling. At the same time, we have developed a method for manufacturing black matte-like stretched containers with drop strength.

  Therefore, the subject of this invention is providing the manufacturing method of the black mat-like extending | stretching container which made the raw material the black polyethylene terephthalate resin which does not peel and maintains a matte tone.

In order to solve the above technical problems, the present invention provides a bottomed cylindrical preform obtained by injection molding in which a black pigment as a colorant and a dispersant for this pigment are mixed in a polyethylene terephthalate resin. A method of manufacturing a black matte-like stretched container using a molded body, wherein the polyethylene terephthalate resin has an intrinsic viscosity in the range of IV = 0.66 to 0.85, and is a bottomed cylindrical premolded body by injection molding together forming a not deform when issuing preparative this pre-molded body flickering - temperature was cooled to 7 to 10 ° C, subsequently sent to the heating step, 83 to the inner surface of the stretch formable minimum temperature of the pre-molded body to cool until 8 8 ° C, heating the exterior surface to 95 to 110 ° C, followed by blow molding process, the mold has a gist that the stretch blow molding in a state of being heated to temperatures higher than 70 ° C The

  According to the configuration as described above, the pre-molded body is stretched in a crystallization (whitening) manner, or a pigment that looks like a matte is mixed, or fine powder particles are not dispersed and mixed. Although it is a stretching container using a black colorant, it can be made into a matte tone, and a stretching container having a drop strength can be obtained without fear of peeling.

Therefore, this invention has the following effects.
As described above, according to the present invention, as in the conventional method, the pre-molded body is stretched while crystallizing (whitening), or a pigment that looks like a matte is mixed, or a fine powder or granular material is formed. While being a stretching container using a black colorant without being dispersed and mixed, it is possible to obtain a stretching container having a drop strength without any fear of causing a matte tone and a separation. Further, particularly, in the heating step, to cool the inner surface of the preformed body to 83-8 8 ° C of stretching lowest possible temperature, the outer surface of 95 to 110 ° C, that is, the next stretch blow molding By heating the surface to a matte tone in the process, it is possible to realize an appropriate matte feeling in the stretch blow molding process and a stretch molding that does not peel off. Furthermore, in the blow molding process, stretch blow molding was carried out in a state where the mold was heated to a high temperature of 70 ° C. or higher, thereby eliminating the gloss on the outer surface of the stretch container and obtaining an appropriate mat feeling.
In the pre-molded body molding step, only the inner and outer surfaces of the pre-molded body are cooled to a temperature that does not deform when the pre-molded body is taken out, that is, for example, the cooling time is 2 to 3 seconds and the chiller water temperature is It is because it is desirable to deliver to the next heating process by the highest temperature which does not deform | transform when this premolded body P is taken out by cooling at 7-10 degreeC.

Also, occurs peeling pole limit viscosity is 0.66 or less, the reverse without the intrinsic viscosity is 0.85 or matte transfer and surface of the resin obtained, matte express It has such.

Furthermore, as described in claim 2, it is desirable that the stretch ratio at the time of stretch blow molding is set to 1.5 to 3 times the longitudinal stretch ratio and 3 to 5 times the lateral stretch ratio.
A high stretch ratio is desirable to obtain a proper mat feeling, but the peeling phenomenon cannot be avoided. Conversely, a low stretch ratio is desirable to avoid the peeling phenomenon, but an appropriate mat feeling cannot be obtained. This longitudinal and transverse stretch ratio could be derived by combining these mutually contradictory desires with factors that achieve both functions as much as possible. In the end, a good mat feeling was obtained, and even when stretch-molding, a state without peeling was successfully exhibited.

As described in claim 4, it is desirable to employ a black iron oxide pigment or a fired black pigment of a metal oxide as the colorant.
This is because the pigment as the colorant is easily compatible with the polyethylene terephthalate resin of the fabric and exhibits a good matte tone.

  In the case where the black mat-like stretched container and the production method thereof according to the present invention are applied to a black mat-like stretched PET bottle which is an example of a black mat-like stretched container, a method for obtaining this will be described first.

  First, as shown in FIG. 1A, 10 parts by weight of a masterbatch comprising 10 parts by weight of a black iron oxide pigment and 1 part by weight of a fatty acid ester dispersant in 100 parts by weight of a polyethylene terephthalate resin with IV = 0.80. Then, 100 parts by weight of the polyethylene terephthalate resin is put into a hopper 2 of an injection molding machine (specifically, an in-line screw type injection molding machine) 1, and the polyethylene terephthalate resin is rotated by a screw 4 that rotates while being heated and melted in a cylinder 3. A black iron oxide pigment and a fatty acid ester dispersant are thoroughly mixed, and the molten mixture M is extruded from the cylinder head into the split mold 5 to form a bottomed cylindrical pre-molded body having a screw thread ( Preform) P is obtained. In the figure, 6 is a heating cylinder and 7 mold heater.

  In this case, in order to improve the dispersion state of the black iron oxide pigment as the colorant with respect to the polyethylene terephthalate resin, the injection screw has a length / diameter ratio (L / D value) of 20 or more, preferably as shown in FIG. Is desirably 25 or more.

  The intrinsic viscosity of the melted polyethylene terephthalate resin is preferably IV value = 0.66 to 0.85. If it is 0.66 or less, peeling occurs due to dropping, and conversely if it is 0.85 or more, the transfer property of the resin and the matte feeling on the surface cannot be obtained, and the matte tone does not appear.

  Next, as shown in FIG. 1 (B), only the inner and outer surfaces of the molded bottomed tubular pre-formed body P are rapidly cooled in a short time. In this case, it is desirable to transfer to the next heating step at the highest temperature that does not deform when the pre-molded body P is taken out.

  Next, the bottomed cylindrical pre-formed product P whose surface was rapidly cooled in a short time (for example, the cooling time was 2 to 3 seconds and the chiller water temperature was cooled to 7 to 10 ° C.) was sent to the heating step. Here, as shown in FIG. 1 (C), the inner surface of the cylinder is cooled by the cooling air blown from the extending rod 8 inserted therein. Further, the outer surface of the cylinder is overheated by the heater 9 surrounding the periphery.

  In this heating step, the cooling temperature of the cylinder inner surface of the bottomed cylindrical pre-formed product P is desirably 83 to 88 ° C., which is the lowest temperature that can be stretched in the next stretch blow molding step. Further, the heating temperature of the outer surface of the cylinder is a temperature immediately before the polyethylene terephthalate resin is crystallized, that is, a maximum temperature that can be stretched in the next stretch blow molding process, in other words, a range that is overheated to a matte tone. It is desirable that it is 95-110 degreeC which is. Both of them are for realizing a proper mat feeling in the next stretch blow molding process and stretch molding without peeling.

The bottomed cylindrical pre-formed product P thus processed is sent to the next stretch blow molding step. As shown in FIG. 2, the bottomed cylindrical pre-formed product P is accommodated in the split mold 10 in which the target bottle shape is formed on the inner wall while the processing temperature in the previous step is maintained (pinched), A bottle V having a desired shape is formed by blowing high-pressure air from the stretching rod 11 inserted into the bottomed cylindrical pre-molded body.

  In this stretch blow molding process, the temperature of the split mold 10 is desirably high, and is preferably 70 ° C. or higher. This is to eliminate the gloss on the outer surface of the bottle and obtain an appropriate matte feeling.

  Further, it is also desirable from the standpoint of emphasizing the matte tone to process the inner surface of the mold to a surface roughness of # 24 to 100 by a method such as sand blasting or shot blasting as necessary.

  The stretch ratio in the stretch blow molding process is preferably high stretch molding in order to obtain an appropriate mat feeling, and low stretch molding is desirable to avoid the peeling phenomenon, to obtain an appropriate mat feeling and avoid the peeling phenomenon. This has conditions that are incompatible with each other.

  Therefore, in the present invention, both factors are comprehensively combined, and as shown in FIG. 4, the longitudinal draw ratio (A ′ / A in FIG. 4) is 1.5 to 3 times, and the transverse draw ratio is When B ′ / B in FIG. 4 was set to 3 to 5 times, a bottle V that maintained a preferable matte tone and did not cause surface peeling was obtained as intended.

  In the figure, A represents the dimension from the bottom of the stopper receiving part to the bottom of the bottomed cylindrical pre-formed product P, and A ′ represents the dimension from the bottom of the stopper receiving part to the bottom of the molded bottle. Further, B represents the diameter of the body portion integrally connected downward from the stopper receiving portion of the bottomed tubular pre-formed body P, and B ′ represents the lateral width of the bottle after molding.

  A more desirable value for the draw ratio is 1.8 to 2.5 times for the longitudinal draw ratio and 3.5 to 4.5 times for the transverse draw ratio.

Next, a case where the black mat-like stretched container according to the present invention is applied to a black mat-like stretched PET bottle which is an example of a black mat-like stretched container will be described.
The bottle V actually formed by the above manufacturing method is filled with 400 ml of water, capped, and dropped upright from a height of 100 cm to the top of the concrete in an environment of 5 ° C and 55% humidity. In addition, when the side dropping was performed once and the presence or absence of peeling was visually confirmed, no peeling was observed in 10 out of 10 pieces.

  In addition, the molded bottle V was cut into a flat surface and measured with a digital glossiness measuring instrument set to measure at an incident angle of 60 degrees. As a result, it was confirmed that a matte feeling was exhibited with a glossiness value of 1 to 10%. did it.

  The polyethylene terephthalate resin employed as the material for the black matte-like stretched container according to the present invention includes a polyethylene terephthalate polymer, a copolymer in which the terephthalic acid component of polyethylene terephthalate is partially replaced with an isophthalic acid component, and ethylene glycol of polyethylene terephthalate. The copolymer was selected from a copolymer in which the component was partially replaced with cyclohexanedimethanol component, and a copolymer in which the terephthalic acid component of polyethylene terephthalate was partially replaced with isophthalic acid component and the ethylene glycol component was partially replaced with cyclohexanedimethanol component. There is at least one type.

In addition to the black iron oxide pigment, a fired black pigment of a metal oxide can be employed as the colorant. It is easily compatible with the polyethylene terephthalate resin of the fabric and exhibits a good matte tone. Although the addition amount of a coloring agent is not limited, 0.01 to 10 weight% is preferable with respect to a molded article. If the added amount of the colorant is less than 0.01% of the molded product, the molded product is not sufficiently colored. Conversely, if it exceeds 10% by weight, it is difficult to uniformly disperse the colorant, and the mechanical properties of the molded product are difficult. May adversely affect the strength.

  Further, the dispersant may be a fatty acid ester type, a fatty acid amide type, or a combination thereof. The above-mentioned colorant as a colorant can be made into a good dispersion state, is difficult to peel off, and a strong bottle V can be formed. Although the addition amount of a dispersing agent is not specifically limited, 1-60 weight% is preferable with respect to a coloring agent. If it is less than 1% by weight, the colorant dispersing effect cannot be obtained, and if it exceeds 60% by weight, the moldability is lowered.

  A master batch containing a colorant and a colorant dispersant in a high concentration can also be used. Moreover, the mixing method to the polyethylene terephthalate resin of a coloring agent and a dispersing agent is not specifically limited, The method normally used in order to disperse | distribute a coloring agent to resin other than the method by the above-mentioned masterbatch can be used.

Shows the preparation of black matte stretched bottle according to the present invention, represents a forming process flop les moldings in-line screw type injection molding machine, (A) extrusion step, the (B) is the quick cooling step, (C) These are explanatory drawings of a heating process. It is explanatory drawing of the stretch blow molding process following FIG. It is explanatory drawing of the L / D value in the injection screw of an in-line screw type injection molding machine. It is explanatory drawing showing the setting method of the draw ratio in a stretch blow molding process.

10 ... Mold P ... Pre-molded body V ... Bottle

Claims (4)

This is a method for producing a black mat-like stretched container using a bottomed cylindrical pre-molded product obtained by injection molding in which a black pigment as a colorant and a dispersant for this pigment are mixed in a polyethylene terephthalate resin. Te, the intrinsic viscosity of the polyethylene terephthalate resin while molding a bottomed cylindrical preformed body by injection molding in the range of IV = .66 to 0.85, does not deform when issuing preparative this pre molded body fliers - temperature was cooled to 7 to 10 ° C, subsequently sent to the heating step, to cool the inner surface of the pre-molded body to 83-8 8 ° C of stretching lowest possible temperature, the outer surface 95 to 110 ° C And then blow-molding the mold at a high temperature of 70 ° C. or higher in a blow molding step. The method for producing a black matte-like stretched container according to claim 1 , wherein the stretch ratio in stretch blow molding is set such that the longitudinal stretch ratio is 1.5 to 3 times and the lateral stretch ratio is 3 to 5 times . Polyethylene terephthalate resin is a polyethylene terephthalate polymer, a copolymer in which the terephthalic acid component of polyethylene terephthalate is partially replaced with an isophthalic acid component, a copolymer in which the ethylene glycol component of polyethylene terephthalate is partially replaced with a cyclohexanedimethanol component, and polyethylene Part of the terephthalic acid component of terephthalate
The method for producing a black mat-like stretched container according to any one of claims 1 to 2, which is at least one selected from a copolymer in which an ethylene glycol component is partially replaced with a cyclohexanedimethanol component by replacing with an isophthalic acid component . The method for producing a black matte-like stretched container according to any one of claims 1 to 3, wherein the colorant is a black iron oxide pigment or a fired black pigment of a metal oxide .

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