JP2674433B2 - Crushable container - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a collapsible container using liquid crystal polyester, and more specifically, it has an air bag preventing property (non-restoring property) desired for extruded tubes and the like, and further has oxygen and water content. , A liquid crystal resin-containing collapsible container having barrier properties against aroma components and the like.

[0002]

Crushable containers, for example extruded tubes for containing toothpaste, cosmetics, or highly viscous liquid articles such as foods, or for containing viscous foods such as ketchup, mayonnaise, jams and chocolates. Known squeeze bottles are those made of various flexible laminates.

As a plastic laminate constituting a collapsible container, an oxygen barrier resin such as ethylene-vinyl alcohol copolymer or nylon is used as an intermediate layer, and an olefin resin such as polyethylene is laminated on both sides thereof. It has been used (Japanese Patent Laid-Open No. 55-5311).

However, unlike a collapsible container made of aluminum foil or an aluminum foil plastic laminate, the plastic collapsible container is subjected to a certain pressing deformation, and when this is released, the original container shape is quickly restored. The problem is that the air bag property, i.e., the resilience, is excessively large.For this reason, when the product is sealed with a lid and stored again after use, a large amount of air is sucked into the container, and as a result, the contents are There is a drawback that it is deteriorated by oxygen in the container.

Japanese Examined Patent Publication No. 62-41942 includes an oxygen barrier thermoplastic resin layer, a moisture resistant thermoplastic resin layer, and a thermoplastic resin blend layer having flake pigments or flake fillers distributed in layers. A squeezed container having a multilayered laminated structure and excellent in air bag prevention is described.

[0006]

According to the above-mentioned prior art, when a thermoplastic resin blended with a flake pigment or the like is formed into a layer and co-melt extruded together with the oxygen barrier resin layer and the moisture resistant resin layer, the flakes are formed. The pigment-like pigment or the like is oriented along the extrusion direction and along the surface of the vessel wall, which gives a tendency to plastically deform due to stress.

However, in this prior art laminated formation, there is a tendency that a sufficient air bag prevention property cannot be obtained unless the ratio of the thickness of the flake pigment-containing resin layer to the thickness of the vessel wall is set to a considerably large value. It is not yet satisfactory in terms of weight reduction. Further, when a flake pigment is blended with a thermoplastic resin, its melt viscosity becomes high, and the melt moldability is lowered with a blending amount such that air bag is prevented, and the flake pigment blended resin layer is ruptured during molding. Alternatively, it is often difficult to obtain a stable air bag prevention property because the thickness largely changes.

Further, the flake pigment-containing resin layer used in the above-mentioned extrusion container itself does not have a gas barrier property against oxygen and water vapor, and requires an oxygen barrier resin layer in addition to it, so that the laminated structure is complicated. There is also the drawback that it will change.

The inventors of the present invention melt-molded a blend containing a thermoplastic resin and a liquid crystal polyester, and at the time of this melt-molding, the liquid crystal polyester was dispersed in a continuous phase of the thermoplastic resin in a particulate form. When making a structure,
It has been found that the formed container becomes plastically deformable and the barrier property against water vapor is also improved.

That is, an object of the present invention is a collapsible container using liquid crystal polyester, which has an air bag preventing property (non-restoring property) desired for extruded tubes and the like, and further has oxygen, water, aroma components and the like. Another object of the present invention is to provide a crushable container containing a liquid crystal resin, which has a barrier property against the above.

[0011]

According to the present invention, the melting index is not less than 1 g / 10 min and less than 20 g / 10 min.
High density polyethylene and liquid crystal polyester of 99: 1 or more
Formed by melt molding of a blend containing above and in a weight ratio of less than 40:60, and having a high density of liquid crystalline polyester
A collapsible container is provided which has a structure in which particles are dispersed in a continuous phase of polyethylene .

In the present invention, the high density polyethylene and the liquid crystal polyester are 99: 1 or more and less than 40:60.
It is preferable to form the container with the blended material contained in a weight ratio of 1. The high density polyethylene has a melt flow rate (MFR-melting index) of 1 g / 10 min or more 20
High density polyethylene in the range of less than g / 10min
It is . Furthermore, liquid crystal polyester has a particle size of 0.1.
It is preferable to exist as spherical or flake-shaped particles having a particle size of from 50 to 50 μm.

[0013]

In the present invention, liquid crystal polyester and a predetermined high density are used.
The first feature is to subject the polyethylene to melt molding in the form of a blend. For liquid crystal polyester,
It has been found that blending a predetermined high-density polyethylene improves its melt moldability, and, for example, in the case of extrusion molding, the drawdown property found in conventional liquid crystal polyester and liquid crystal polyester-containing resin compositions is significantly improved. .

Even in the case of injection molding, since the melt of liquid crystal polyester and its blend has a very large melt flow orientation, the melt tends to flow one-dimensionally, so that the melt in the injection mold is likely to flow. difficult to uniformly distributed in, there is a problem that it is difficult to obtain a uniform wall thickness of the molded article, the liquid crystal resin and a predetermined high density polyethylene
When the blended product with a resin is used for injection molding, a molded product (container) having a high precision according to the shape and dimensions of the injection mold can be produced.

According to the present invention, a container excellent in shape and size reproducibility can be obtained in this manner, but at the same time, liquid crystal polyester is dispersed in a particulate form in a continuous phase of a predetermined high density polyethylene . The expression of a distribution structure is the second and most important feature. That is, in the collapsible container of the present invention, the predetermined high-density polyethylene is a continuous phase,
Since the liquid crystal polyester has a structure in which it is dispersed in the form of particles, plastic deformability is imparted to the container wall when it is pressed, and when used as a collapsible container, the air bag prevention property is significantly improved. Further, in the collapsible container of the present invention, the barrier structure (gas permeation resistance) against water vapor and oxygen can be remarkably improved by adopting the above distribution structure.

FIG. 1 shows high density polyethylene (HDP).
E) and a graph plotting the relationship between the restoration angle from 180 degree bending and the elapsed time (seconds) for a section cut from the body of a tubular container formed by mixing 10% by weight of liquid crystal polyester with HDPE. (Refer to the section of Examples described later for details). Although the melt flow rate (MFR-melting index) of HDPE increases in the order of Comparative Example 1, Example 1, and Example 2, it can be seen that the restoration angle decreases accordingly. When the MFR is less than 0.1, the liquid crystal polyester is dispersed in a fibrous state, and due to the rigidity of the liquid crystal polyester itself, sufficient crushability cannot be obtained.
When the MFR is in the range of 0.1 to 20, the liquid crystal polyester is dispersed in the form of very short fibers or particles, and plastic deformability is exhibited. In addition, even with a high MFR for injection molding, the drawdown property is improved by blending the liquid crystal polyester, and extrusion blow molding becomes possible. But MFR
Is more than 20, drawdown cannot be prevented, and it becomes very difficult to form a container having a uniform thickness by extrusion blow molding.

"FIG. 2" shows HDPE and a section cut out from the body of a tubular container formed by blending HDPE with liquid crystal polyester in an amount of 10 and 30% by weight.
It is the graph which plotted the relationship between the restoration angle from 80 degree bending and elapsed time (second) (for details, refer to the section of the Example mentioned later). If the liquid crystal polyester content is less than 1% by weight, the air bag cannot be sufficiently prevented and the gas barrier property cannot be obtained. On the other hand, if it exceeds 60%, the liquid crystal polyester becomes a continuous phase, so that the molded container becomes extremely hard and brittle, and cannot be practically used as a tube or a squeeze bottle.

FIG. 3 shows HDPE, low density polyethylene (LDPE) and LDPE with 50 liquid crystal polyesters.
It is the graph which plotted similarly the relationship between the restoration angle from 180 degree bending and elapsed time (second) about the section cut out from the trunk | drum of the tubular container shape | molded by mix | blending by weight%. See example section). LDPE is most widely used as a main material for extruded tubes and squeeze bottles because of its flexibility (low elastic modulus). However, from the viewpoint of air bag prevention, HDPE
It can be seen that the restoration angle is much larger than that of and is disadvantageous.

From these "FIGS. 1", "2" and "FIG. 3", a predetermined high density polyethylene is blended with a liquid crystal polyester, and the liquid crystal polyester is dispersed in a particulate form in the continuous phase of the high density polyethylene. It is understood that by adopting a different structure, the resilience can be significantly reduced. The above fact was found as a phenomenon,
The reason is not clear, the continuous phase is a soft structure high-density polyethylene, has a liquid crystal polyester rigid structure dispersed in particulate, liquid crystal polyester dispersed particles each other after deformation, high density polyethylene phase It is presumed that they interlock with each other to form a new structure and act to prevent the restoration after deformation.

FIG. 4 shows a tubular container formed of HDPE alone and a tubular container formed of a blend of HDPE and 10% by weight of liquid crystalline polyester, in which the liquid crystalline polyester is dispersed in particles. 6 is a graph in which the relationship between the elapsed time and the decrease in water content in the container is plotted (for details, see the section of Examples described later).

From this graph, it is understood that by blending the liquid crystal polyester, the amount of water vapor permeation through the container wall is suppressed to a low value.

[0022] In the present invention, the predetermined high density polyethylene and the liquid crystal polyester 99: 1 or more and 40:60 Not
It is preferred to form the container with the blend containing the full weight ratio. If the compounding amount of the liquid crystal polyester is less than the above range, the air bag preventive property is insufficient, while if it is more than the above range, the melt moldability tends to decrease.

The high density polyethylene used has a melt flow rate (MFR-melting index) of 1 g / 10 mi.
It is a high-density polyethylene in the range of n or more and less than 20 g / 10 min . High density poly with MFR in this range
Ethylene has melt flow characteristics suitable for dispersing the liquid crystal polyester in a granular state, and is also excellent in extrusion characteristics of the content.

Further, the liquid crystal polyester has a particle size of 0.
The particles preferably exist as spherical or flake particles having a particle size of 1 to 50 μm, and outside the above range, the air bag prevention property tends to be lower than that within the above range.

[0025]

BEST MODE FOR CARRYING OUT THE INVENTION

(Liquid Crystal Polyester) In recent years, liquid crystal polymers have attracted attention in the field of fibers due to their excellent mechanical properties. This liquid crystal polymer includes one that forms a liquid crystal in a solution (dope) state (lyotropic) and one that forms a liquid crystal in a molten state (thermotropic). The former is represented by Kevlar (DuPont). Is an aromatic polyamide,
The latter is an aromatic polyester represented by Vectra (Celanese Company). In the present invention, liquid crystal polyester is used because a crushable container is manufactured by melt molding.

As the liquid crystal polyester resin, a polyester derived from a polycondensation of an aromatic dicarboxylic acid component and an aromatic diol component; a polyester obtained by polycondensation of an aromatic hydroxycarboxylic acid; a copolymerization of the above two polyesters. Thermotropic substances such as polyesters; and copolyesters of these polyesters and polyethylene terephthalate can be used.

The proportion of divalent aromatic groups per divalent hydrocarbon group in all ester repeating units is, for example, 50% in polyethylene terephthalate, but in the range of 50 to 100% in the liquid crystal resin used in the present invention. Is desirable.

A suitable example is as follows.

Equation (1)

Embedded image A polyester composed of repeating units represented by, for example, Vectra from Celanese,

Equation (2)

Embedded image Polyester consisting of repeating units represented by, for example, Zider from Dartco,

Equation (3)

Embedded image A polyphenylhydroquinone terephthalate consisting of repeating units of

Equation (4)

Embedded image PHB / PET copolymer comprising repeating units of.

Of course, the liquid crystal polyester used in the present invention is not limited to these examples. The liquid crystal resin used in the present invention should have a molecular weight sufficient to form a film, and is generally preferably one that can be thermoformed at 200 to 400 ° C. The liquid crystal polyester of "Chemical Formula 4" is particularly suitable for the purpose of the present invention.

[0034] As (high density polyethylene) high density polyethylene, those used in the manufacture of containers and other resin molded product is Ru are preferably used.

These high-density polyethylenes have 1 g / 1
0 min or more and less than 20 g / 10 min, especially 1 to 10
well that has a MFR of g / 10min, depending on the molding method, Ru can be appropriately selected and used those things or injection grade extrusion grade. The blend containing the high-density polyethylene has particularly good melt moldability, and is particularly excellent in the appearance of the above-mentioned grain distribution structure. As high density polyethylene, the density is 0.95 to 0.97g / c
m ³ is better.

The collapsible container according to the present invention is generally composed of a high-density polyethylene which is mainly distributed in layers on the inner and outer surface sides and also exists as a continuous phase in the central portion, and a liquid crystal polyester which is mainly distributed in the central portion in the form of particles. Become.

In FIGS. 5, 6, and 7 showing an example of the collapsible container of the present invention, the collapsible container is composed of a tubular container 1 and a lid 2 and is tubular. The container 1 has a screwed extrusion port 3 integrally formed by hollow molding of a parison, a conical shoulder portion 4 continuous with the extrusion port 3, and a tubular body portion 5. This tubular body portion 5 has a cut edge portion 9, and the inner surface portions 10 and 1 of the body portion 9 facing each other.
Zeros are fused together to form the bottom.

In FIG. 7 showing an enlarged cross-sectional structure of the body, the vessel wall is composed of an inner and outer surface layer 6 mainly made of high-density polyethylene and a central portion 7. It is composed of a continuous phase 8 of a plastic resin and a liquid crystal polyester 11 dispersed therein in a particulate form. It is recognized that such a dispersed structure effectively prevents restoration after deformation.

(Production Method) In the present invention, the liquid crystal polyester and the high density polyethylene are used.
Len is fed in the form of a mixture to the hopper of the extruder. This mixture may be a dry blend of the two or a melt blend. Dry blending can be performed using various mixers such as ribbon blender, conical blender, and Henschel mixer, while melt blending is performed using a single-screw or twin-screw extruder, kneader, Banbury mixer, roll, etc. You can

In molding the blend, injection molding or extrusion molding can be used. At the time of molding, as described above, the two resins are sufficiently mixed, but the conditions under which the melt flow orientation of the liquid crystal polyester is not sufficiently performed should be selected, and moreover, the blended product is sufficiently fluidized. The conditions should be selected. From this point of view, high density
As the polyethylene, it is preferable to use one having a high melt fluidity, particularly one having an MFR within the above-mentioned range, and the molding temperature of the resin is relatively high.
It is preferably 0 ° C., particularly 200 to 300 ° C.

In molding, the mixture is melt-injected into a cooled injection mold. An injection machine known per se equipped with an injection plunger or a screw is used, and the mixture is injected into an injection mold through a nozzle, a sprue and a gate. As a result, the above-described distribution structure is formed in the resin flow, and the liquid crystal resin is provided with appropriate dispersibility, flows into the injection mold cavity, and is cooled and solidified to be the collapsible container of the present invention. As an injection type,
Although one having a cavity corresponding to the shape of the container is used, it is preferable to use a one-gate or multi-gate injection mold. Injection pressure is 100 to 2000kg / c
m ² is preferable.

In the case of extrusion molding, an extruder equipped with an arbitrary screw is preferably used as the extruder. As a die, a ring die is used for forming a tube, a pipe and a parison. By hollow molding the extruded parison, a collapsible container such as a bottle or a tube is molded.

[0043]

The present invention is further described by the following examples. As an evaluation method of the air bag prevention property, after filling 120 g of toothpaste into the molded tube and heat-sealing the bottom part, pressing the approximately central part of the tube and squeezing out about half of the filling amount, the state of the air bag after that Was visually observed. In addition, in order to make a more detailed comparison regarding the crushability, a length of 7 cm and a width of 2 are measured along the height direction from the center of the body of the tube.
Cut out a piece of cm, and fix it at a position of 2 cm from one end on a horizontal table with the inner surface facing down, and bend 180 degrees 5
After holding for 2 seconds, the restoration angle of the longer end after 5, 15, 30, and 60 seconds was measured. This is shown in Table 1.

In order to evaluate the moisture barrier property, the mouth of the tube was heat-sealed with the aluminum foil plastic laminate, then 120 cc of water was filled from the bottom, and the bottom was heat-sealed for sealing. This was stored in dry air at 50 ° C., and the change in weight was measured at appropriate intervals. Table 2
Shown in The dispersed state of the liquid crystal polyester was obtained by cutting out a section from the center of the body of the tube, collecting a sample with a thickness of 10 μm from the cross section including the height direction and the thickness direction using a microtome, and measuring the shape and size of the particles with an optical microscope. Was observed.

Example 1 MFR defined by JIS K 6760 is 1.0 g / 10.
HDPE of min and liquid crystal polyester having the structure of "Chemical formula 4" are mixed in a weight ratio of 90:10, and the height of the body is 100 mm, the diameter of the body is 40 mm, and the body wall A cylindrical tube container having an average wall thickness of 300 μm and an internal volume of 120 cc was molded. The liquid crystal polyester was dispersed in a slightly flattened elliptical shape stretched in the height direction, and the average particle size was about 1 μm. When this tube was filled with toothpaste and the extrudability was examined, almost no air bag was observed.

Example 2 In Example 1, HDPE had MFR of 8.0 g / 10.
A tube container was molded in the same manner as in Example 1 using the min. The liquid crystal polyester was dispersed in almost particle form, and the average particle size was about 1 μm. When this tube was filled with toothpaste and the extrudability was examined, almost no air bag was observed.

Example 3 A tube container was molded in the same manner as in Example 1 except that the weight mixing ratio of HDPE and liquid crystal polyester was 70:30. The liquid crystal polyester was dispersed in almost particle form, and the average particle size was about 5 μm. When this tube was filled with toothpaste and the extrudability was examined, almost no air bag was observed.

Example 4 HDPE having an MFR of 8.0 g / 10 min and liquid crystal polyethylene ester having a structure of "Chemical formula 1" were mixed at a weight ratio of 50:50 and melt-kneaded at 290 ° C. using a twin-screw extruder. The same HD as the one used as the masterbatch for kneading
PE was mixed in a weight ratio of 20:80 (so that the liquid crystal polyester finally became 10% by weight), and a tube container was molded in the same manner as in Example 1. The liquid crystal polyester was dispersed in almost particle form, and the average particle size was about 10 μm. When this tube was filled with toothpaste and the extrudability was examined, air bags were hardly seen.

Comparative Examples 1 and 2 In Example 1, the MFR of HDPE was 0.1 g / mi.
A tube container was molded in the same manner as in Example 1, with n as Comparative Example 1 and 20 g / 10 min as Comparative Example 2. In Comparative Example 1, the liquid crystal polyester was strongly stretched in the height direction and dispersed in a fibrous state. When this tube was filled with toothpaste and examined for extrudability, it was not possible to form a tube having a uniform wall thickness that could be practically used.

Comparative Example 3 A tube container was molded by the same method as in Example 1 using HDPE alone having an MFR of 0.3 g / 10 min. In this example, the moldability was good, but clear flow marks were generated and the appearance was poor. When this tube was filled with toothpaste and the extrudability was examined, some air bags were observed.

Comparative Example 4 A tube container was molded by the same method as in Example 1 using HDPE alone having an MFR of 8.0 g / 10 min. In this example, drawdown was severe and a tube having a uniform wall thickness could not be obtained.

Comparative Example 5 A tube container was molded in the same manner as in Example 1 except that the weight mixing ratio of HDPE and liquid crystal polyester was 40:60. The molded tube container was brittle and easily broken, and could not be put to practical use.

Comparative Example 6 A tube container was molded by the same method as in Example 1 using LDPE alone having an MFR of 0.3 g / 10 min. When this tube container was filled with toothpaste and the extrudability was examined, a considerable amount of air bag was generated.

Comparative Example 7 LDPE having an MFR of 8.0 g / 10 min and liquid crystal polyester having a structure of "Chemical formula 4" were mixed in a weight ratio of 50:50, and a tube container was molded in the same manner as in Example 1. . When this tube was filled with toothpaste and the extrudability was examined, some air bags were observed.

[0055]

[Table 1]

[0056]

[Table 2]

[0057]

According to the present invention, a blend of a liquid crystal polyester and a predetermined high density polyethylene is melt-molded,
By dispersing the particles in the continuous phase of high-density polyethylene in the center of the molded container in a particulate form, it becomes possible to impart plastic deformability to the molded container when pressed, and an airbag desired for an extruded tube or the like. It has become possible to provide a collapsible container containing a liquid crystal resin, which has a preventive property (non-restoring property) and also has a blocking property (barrier property) against oxygen, moisture, aroma components and the like.

[Brief description of the drawings]

Figure 1: High density polyethylene (HDPE) and HDP
The section cut out from the body of the tubular container formed by mixing E with 10% by weight of liquid crystal polyester was 18
It is the graph which plotted the relationship between the restoration angle from 0 degree bending, and elapsed time (second).

Figure 2: High density polyethylene (HDPE) and HDP
3 is a graph in which the relationship between the restoration angle from 180 degree bending and the elapsed time (seconds) is plotted for a section cut out from the body of a tubular container formed by mixing E with 10 and 30% by weight of liquid crystal polyester. .

FIG. 3 shows the restoration angle from 180 degree bending and the elapsed time for HDPE, low-density polyethylene (LDPE), and LDPE blended with 50% by weight of liquid crystal polyester and cut from the body of a tubular container. Seconds)
It is the graph which similarly plotted the relationship with.

FIG. 4 shows the elapsed time with respect to a tubular container formed of HDPE alone and a tubular container formed from a blend of HDPE and 10% by weight of a liquid crystalline polyester in which the liquid crystalline polyester is dispersed in a particulate form. It is the graph which plotted the relationship with the weight loss of the water | moisture content in a container.

FIG. 5 is an external plan view showing an example of the collapsible container of the present invention.

FIG. 6 is a cross-sectional view of the collapsible container of “FIG. 5”.

FIG. 7 is an enlarged cross-sectional view of the container wall of the collapsible container of FIG.

[Explanation of symbols]

1 is a tubular container, 2 is a lid, 3 is an extrusion port with a screw, 4
Is a conical shoulder, 5 is a tubular body, and 6 is mainly high-density
Inner and outer surface layers made of polyethylene , 7 in the center, and 8 in high density
Degree polyethylene continuous phase, 9 cut edges, 10
Is an inner surface of the body facing each other, and 11 is a liquid crystal polyester dispersed in particles.

Claims (2)

(57) [Claims] 1. A melting index of 1 g / 10 min or more and 20 g
Formed by melt molding of a blend containing a high density polyethylene of less than / 10 min and a liquid crystal polyester in a weight ratio of 99: 1 or more and less than 40:60 , and the liquid crystal polyester is a continuous high density polyethylene . A crushable container having a structure in which particles are dispersed in a phase. 2. The collapsible container according to claim 1, wherein the liquid crystal polyester is present as spherical or flake particles having a particle size of 0.1 to 50 μm.