JPS61120719A - Molding process of vinylidene chloride-methyl acrylate family copolymer, using extruding process in molten state - Google Patents

Abstract

PURPOSE:To contrive to supply stably VDC-MA extruded product with high market request by using vinylidene chloride-methyl acrylate family copolymer (herein under mentioned as VDC-MA) prepared under a specified condition. CONSTITUTION:VDC-MA is prepared in such a manner that the relation of weight- average molecular weight having 3-15wt% MA component to 100wt% copolymer and the value of 70,000-250,000 measured by gel permeation chromatography method, to the contained ratio of copolymer contained in copolymer with molecular weight equal to 20,000 or less, becomes the value in the range of the quadrilateral defined by the straight line connecting four coordinate points, i.e. point A (70,000, 18), point B (150,000, 4), point C (250,000, 4) and point D (120,000, 18) in a normal coordinates with both logarithms graduated respectively such that average molecular weight is graduated on an abscissa (logarithmic scale) and the contained ratio of the copolymer with 20,000 or less molecular weight is graduated on an ordinate (logarithmic scale). Thus prepared material is used for VDC-MA. The contained amount of MA component is kept at 15% or less, and also a little modifying agent which does not remarkably deteriorate gas barrier property is added, whereby extruding moldability may be kept at excellent state.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to an improvement in a melt extrusion processing method for a vinylidene chloride-methyl acrylate copolymer.

(Prior art and problems to be solved by the invention) Vinylidene chloride-methyl acrylate copolymer (hereinafter referred to as VD
O-MA) has been generally treated as a type of vinylidene chloride copolymer, that is, as an equivalent of vinylidene chloride-vinyl chloride copolymer. In addition, as a molding method using a melt extrusion method for these copolymers, the copolymer is melt-kneaded in an extruder, extruded alone or in layers with other resins, for example, into a cylindrical shape, and then cooled and solidified. do,
(Japanese Patent Publication No. 44-32676), for example, by inflating a cylindrical extrudate to make a container (Japanese Patent Publication No. 49-198)
(Japanese Patent Publication No. 4855), for example, extruded into a plate shape with a T-die to make a sheet (Japanese Patent Publication No. 52-22676), for example, extruded into a ring shape and biaxially stretched to make a tubular film or a flat film (Japanese Patent Publication No. 52-22676). 31889) is described in each specification and is well known.

On the other hand, similar to the MA acid component in VDO-MA and the vinyl chloride (VC) component in vinylidene chloride-vinyl chloride copolymer (hereinafter abbreviated as vno-vo), the extremely fast heat generation of vinylidene chloride IJ polymer This serves to moderate the decomposition rate and facilitate plastic deformation of the copolymer itself as a whole. VDO-MA is considered to be more effective when it contains an MA acid component than a vc acid component.
If VDO-MA can be industrially molded, extrusion-molded products of VDO-MA, which are more advantageous than VDO-VO in terms of gas barrier properties, should be listed on the market and put into practical use as soon as possible. So 4
However, at present, molded products of vinylidene chloride containing acrylic components that have finally appeared on the market do not rely on the extrusion method described in, for example, Japanese Patent Publication No. 59-23682, but instead use the so-called casting and coating method. This is only a molded product made from vinylidene chloride latex containing acrylic in an emulsion state that is molded by molding or casting.

The reason for this is that, according to the knowledge of the present inventors, VDO-MA has a unique polymerization form in order to make a resin that can withstand extrusion methods, and that the empirical rules and knowledge of VDO-VO co-metallic resins cannot be used. It is not always utilized, and overall research on polymerization conditions is not sufficient. On the other hand, the requirements of those who list resin molded products as products or product packaging materials are based on the existence of a wide variety of similar existing products that are already listed. All aspects, including standards, have been highly improved, and in light of the evaluation criteria for determining commercialization, which is based on the premise of being able to compete with existing products, the current vDo-MA is an extrusion method. This is because the resin is ranked as a resin that cannot be commercialized, and it is not even possible to provide polymer design values for research on the 1st condition.

In other words, the biggest specific drawback of VDO-MA is that even though the knowledge obtained with the O large-diameter extruder can be applied to the small-diameter extruder, the knowledge obtained with the small-diameter extruder is difficult to apply to the large-diameter extruder. Therefore, all basic experiments for improvement must be based on large-diameter extruders with high resin consumption, which has the drawbacks of uneconomical experimental design and difficulty in its execution.

When looking at the labor productivity, design quality level, and sufficiency of a mass production system using a large-diameter extruder, for example, the heat resistance stability, melt flow stability, uniformity of flow development, etc. of the resin are There is a problem with the skeletal factors governing the company, and the current level does not seem to meet the criteria for evaluating the pace of corporateization.

・Although it is possible to improve thermal stability and plastic fluidity by adding plasticizers, modifiers, etc., the magnitude of the negative effect on smooth properties due to the addition of modifiers is limited by VDO-MA development. A fact that negates the very necessity of

It is summarized in

The present invention has been made in view of the current situation and to overcome the problems, and its objectives are: 1. A method that is more efficient and economical than the casting, coating, casting, etc. methods using latex; For example, 5
To improve the technical level of extruders with a large diameter of 0 wmφ or more to the level that can be implemented under industrial standards, thereby making it possible to stably supply VDO-MA extrusion molded products that are in high demand in the market. By giving a target value for the VDO-MA composition, we can facilitate the development of polymerization methods and their conditions.
To facilitate the appearance of further improved VDO-MA extrusion products.

3. R9'r so-called V, which uses less modifiers such as plasticizers
To enable stable supply of VDO-MA extrusion molded products in a state where the essential properties of DO-MA can be fully utilized.

(Means for solving problems) The contents of the present invention will be explained in detail below using drawings and the like.

FIGS. 2 and 3 show VDO-
Oxygen permeation 1 for each MA component ratio of MA sheet
(02TR, unit; 15 tt ・at/m" 24
Hrs-atm ・(at 20℃・65%RH), l
and water vapor transmission amount [WVTR, unit: 15tt・7m
24 Hrs・40'C90%RH) is a graph showing the relationship.

Figure 4 shows the Elmendorf tear strength [unit?] for the same VDO-MA receipt and MA component ratio. ] is a graph showing the relationship.

Therefore, the overall relationship shown in Figures 2 to 4 is whether VDO-MA can maintain a continuous layer state without cracks etc. when it is used medicinally as a gas barrier layer in the form of a single layer or a laminated component layer. This corresponds to a relationship diagram showing the following.

In FIGS. 2 and 3, the smaller the amount of MA components, the lower the
Both 2TR and WVTR show a low permeation amount, indicating that they can form an excellent gas/rear oil layer, but on the other hand, in Figure 4, reducing the MA component it is important in terms of mechanical properties. This clearly shows that this results in a fragile resin layer.

Therefore, when utilizing VDO-MA'ji as a barrier resin layer, it is necessary to select the amount of MA component from the range of 3 to 15% by weight, which requires both mechanical strength and barrier properties. When doing so, it can be said that it is desirable to select one with an MA amount in the range of 5 to 13% by weight.

It is also shown in Figures 2 and 3. , 'r The values of R and WVTR are
A sheet made by extruding VDO-MA in a substantially unplasticized state, in which only 1% by weight of epoxidized linseed oil and 4% magnesium oxide O,4Z, which are called heat stabilizers, are added to the copolymer. With the values shown, it is possible to obtain such a high level of non-reacting properties with VDO-M in a virtually unplasticized state.
It should be noted that A is a major advantage of the process of the present invention, which allows it to be extruded economically and industrially.

As reference values for FIG. 2 (OzT R) and FIG. 3 (WVTR), the characteristic values of commercially available vinyl chloride films and vinylidene chloride films are shown below, with the same unit amounts.

Figure 1 is an analysis diagram. This analysis diagram is also a proof diagram showing the validity of the technical idea of the present invention.

The horizontal axis of Figure 1 is the weight average molecular weight value (according to the GPC method) on a logarithmic scale, and the vertical axis is the copolymer with a molecular weight of 20,000 or less (according to the same GPC method) contained in the copolymer. The content (%) is expressed on a logarithmic scale, and the rectangular coordinates are shown on a double-logarithmic scale. □ What is plotted in this Figure 1 expresses the degree of sufficiency when performing extrusion molding processing in a dry weight system as a comprehensive evaluation. (see table), the results of the comprehensive evaluation are shown in relation to the weight average molecular weight of the corresponding copolymer and the content of copolymers with a molecular weight of 20,000 or less contained in the copolymer.
Shows the analysis results. In addition, in the diagram, the ◎ mark indicates that we are confident enough to produce with industrial equipment, the ○ mark indicates that production with industrial equipment is somehow possible with a partial design change, and the Δ mark indicates that production is possible with industrial equipment. Unsuitable for use, x marks indicate difficulty in obtaining molded products, and all are indicated.

According to FIG. 1, those evaluated as ◎ and ○ have a coordinate relationship distributed inside of those evaluated as Δ and X. What should be noted is that the companies rated ◎ and ○ above are all copolymers obtained by mixing (adjusting) copolymers that were originally rated as X or Δ. The fact is that it is a polymer.

Therefore, in the analysis diagram of FIG. 1, there exists a technical means to improve what was evaluated as unadoptable into something that can be adopted.

The technical idea is shown in FIG. 1 and defined by the present invention, which is expressed by the coordinate points [weight average molecular weight, content of copolymer with a molecular weight of 20,000 or less in the copolymer]: AC70,000, 18
], point B (150,000, 4], point C [250,000, 4], point D (
120,000, 18] are connected by straight lines to form a copolymer that satisfies the relationship within the range of the quadrilateral.

The means of adjustment shown in the present invention is to mix copolymers with each other, but if the skeleton of the target copolymer is specified, it is possible to select polymerization conditions and adjust them to the desired value. Since it is not difficult, the adjustment referred to in the present invention can be understood to include polymerization adjustment.

In addition, with the recent pace of corporateization, extrusion molding processing plants are becoming more labor-saving and resource-saving, and ensuring high labor productivity, along with maintaining a high commercial quality level, is critical to the survival of a company. Control over sexuality itself. From this point of view, it is desirable to point E (80,000, 14) and point F C10 as shown in FIG.
, 50,000, 8], point G [130,000, 8], point H (100,000, 1
4] for values within the range of the quadrilateral connecting the four points with straight lines,
The purpose is to adjust the composition of the copolymer. The technical significance of this is presumed to be that when increasing the content of conjugates with molecules t20,000 or less, the molecular weight distribution of the entire conjugate is adjusted so as not to become too broad. According to research, the weight average molecular weight is in the range of 70,000 to 250,000, and the ratio to the number average molecular weight determined by the same GPC method (i.e., 1 weight average molecular weight ÷ number average molecular weight) is in the range of 2 to 3. It is desirable that the

One of the usefulness of the production method of the present invention is the properties exhibited by the molded article obtained.

To introduce a few of the major ones, the first is the characteristics of the gas barrier shown in Figure 2.3 above.

This gas sludge property is also a property that can be obtained with the same VDO-based copolymers, such as VDO-To, but when using a VC component, the proportion of VO can be adjusted to match the copolymerization when forming a molded product. It is difficult to reduce the proportion to a small amount of 8% by weight or less, and even if this is attempted, the help of a modifier such as a plasticizer is required in relation to extrusion moldability, resulting in a low 0. There is a limit to extracting the value of TR (that is, high resistance).

On the other hand, the VDO-M molded body obtained by the method of the present invention can be extruded by keeping the MA component content at 15% or less and adding a small amount of a modifier that does not significantly contribute to the deterioration of the gas nozzle properties. Since the processability can be maintained in an excellent state, it can be used as a layer material with excellent gas/catalytic properties compared to VDO-VO.

FIG. 5 is a strain-stress relationship graph of the VDO-MA molded product obtained by the method of the present invention, showing a comparison (dashed line) with that of the VDO-VC molded product.

According to FIG. 5, depending on its composition and conditions, the molded product obtained by the method of the present invention elongates when the molded product is stretched, and returns to its original shape when the stretching force is released. This shows that it has the property of returning to a similar state (the part shown by the dashed line), so-called stretch packaging suitability.This property is a unique property that cannot be obtained with the VDO-VC composition. Its utilization is attracting attention.

That is, currently known monolayer films having stretchability include vinyl chloride films and ethylene-vinyl acetate copolymer films, but these have poor resistance to gases including water vapor.

Since there are problems such as loss of weight of the contents of the package, it has become a challenge in the industry to provide stretch films with smoothness. As a solution, lamination with high IJ resin is being considered, but since barrier resins generally cannot be expected to have stretch properties, it is difficult to have both barrier properties and stretch properties. It is.

Under these circumstances, the appearance of VDO-MA, which is easy to mold, is attracting attention as a material that is highly useful when applied as a single layer or as a laminated layer material. In order to effectively exhibit such stretchability, it is desirable to select and use a copolymer containing MA in an amount of 10 to 15% by weight.

Figure 6 is an example of the experimental results showing the yield percentage of stretched and oriented VDO-MA (lol #), in the case of VDO-VC (dashed line).
This is shown in comparison with Although the fly growth conditions for the two are not necessarily the same, they are shown as examples of comparison between the two at the highest level of alignment that can be achieved with each composition.

According to the results shown in Figure 6, VDO-MA has superior shrinkage properties in both low-temperature shrinkage and the amount of shrinkage in a constant temperature range.
It can be seen that it has an excellent property of increasing -VO. This shrinkage performance is, for example, when VDO-MA is used in the gas-no-rya resin layer in a laminated film and used as a whole in a low-temperature shrinkable gas-no-no-rya laminated packaging material for applications such as raw meat packaging. This shows the usefulness of providing a laminated film that has better low-temperature shrinkability than laminated films that come as layers and can be shrink-wrapped tightly without wrinkles.

The second usefulness of the present invention is that molded products having the above-mentioned characteristics can be manufactured using equipment on an industrial production scale, and that it provides various molded products that satisfy quality standards. This is something that can be done.

The reasons for this will be explained below along with the meaning of the evaluation items in the present invention.

First of all, the evaluation items ``thermal stability of resin during extrusion'' and ``incidence of punctures'' are based on, for example, the extruder being operated continuously for a long time to ensure normal quality molding without decomposition products or discolored streaks. It is an indicator that shows how long a product can be continuously produced under set normal operating conditions without the need for recovery/correction work, and is an indicator of product quality and labor productivity (including equipment design).
This corresponds to the basic conditions for setting.

In other words, in manufacturing equipment for industrial production, the above basic conditions assume that continuous production will continue for 10 hours or more on average probability, and based on that premise, for example, the capacity of molded product storage equipment, equipment etc. Automatic interlocking, operating mechanisms, quality adjustment mechanisms, etc. are considered, and the design is designed to minimize the required man-hours and maximize operating conditions. Therefore, if you try to manufacture molded products that do not meet the above basic conditions using equipment with such a design, it will not only take a lot of man-hours to restore the equipment to normal operation, but it will also require The operating rate will drop and the quality of the settings cannot be guaranteed, resulting in a situation where production is no longer possible. On the other hand, in the present invention, since the continuity evaluation, which is the basic condition described above, has been sufficiently evaluated, it can be said that it is possible to manufacture economically competitive molded products that satisfy the set quality. Furthermore, the fact that the "thermal stability of the resin in the extruder" can be maintained at a high level means that the method of the present invention can also be applied to injection extrusion processing that requires intermittent banding of the resin in the extruder. It can be used as a basis.

Next, the "extrusion bed" and "thickness unevenness in the width direction" are both fluid elements that control the uniformity of the thickness in the longitudinal direction and the thickness in the lateral direction of the molded article.

However, in this case, the fact that both of these fluctuations can be maintained at a low level means that the fluidity is excellent in biaxial directions. Furthermore, it is noteworthy that it shows that it is possible to perform economical extrusion using a die with a wide width (or a large diameter), and that it is possible to extrude and expand uniformly even into the holes of a large area.

Moreover, "homogeneous stretchability" corresponds to the main item that determines suitability for stretching processing. In other words, it is a property that controls the quality of the obtained film, such as appearance quality such as color, wrinkles, and bending, mechanical properties such as tear strength and tensile strength, and physical properties such as gas barrier properties and transmission distortion. Therefore, satisfaction of this item is of great significance in obtaining a high quality stretched film.

Next, the meaning of "allowable range of change in extrusion temperature conditions" refers to the method of in-die lamination co-extrusion.
This is an index that indicates the suitability of selecting a partner resin when obtaining injection molding, etc.). In other words, in in-die lamination coextrusion, it is important to approximate the viscosity of the laminated resins, but the wider this tolerance range, the wider the range of selection of resins that can be partners. Therefore, it is significant that it can be used for high-quality laminate products.

Furthermore, the meaning of "laminate extensibility" is that the VDO-MA in the laminate
VDO-MA is used to evaluate whether a layer can expand to keep up with the stretching deformation of other layers, such as when forming a laminate by deep drawing and extrusion, or when forming a laminate into a thin layer by forced stretching. It is significant as a means of evaluating the homogeneous film suitability (i.e., the role mechanism of each layer) of the layer. In the case of the present invention, all of the above-mentioned evaluation items are met at a high level (see Table 3.4), and as a result, various molded products can be economically supplied by industrial sources, making full use of the advantages. , its usefulness can be said to be extremely high.

The weight average molecular weight, number average molecular weight, copolymer content with a molecular weight of 20,000 or less, etc. of VDO-MA in the present invention are determined by the following method, that is, the GPC (gel/J-mini-7 chromatography) method. This is the value obtained.

The equipment used is as follows.

Model 0: High performance liquid chromatography (manufactured by Waters) O column: Microstyradil (same as above) O solvent: Tetrahydrofuran [hereinafter abbreviated as THFt] (manufactured by Wako Tsumugi Co., Ltd., for liquid chromatography) Measurement format is as follows .

Changes in the concentration of the sample dissolved in THF to a concentration of 0.51% by volume over time after injection of the sample when the sample is heated at 20°C and flows out together with the solvent. is detected as the output current value of the differential refractometer and drawn on the chart of the recorder.

Calibration of molecular weight is as follows.

Molecular weight is 3600.35000.110000.650
000.1460000 for each of the five types of monodispersed polystyrenes using this measuring device, and use this data as a calibration curve as the basis for calculating the molecular weight of VDO-MA. In other words, GPC until the peak and value of the output current of the differential refractometer, which is indicated by monodisperse polystyrene of known molecular weight, occurs.
Using the relationship between the count number (number of seconds starting from the time of sample injection as 0) and the molecular weight (semi-logarithm) of the sample as a coordinate point, create a graph connecting these five coordinate points with a straight line, and use this to test molecular weight calculation. It is made with a line.

Measurements and calculations are as follows.

From the relationship chart between the GPC count number drawn for the target resin sample and the output current value of the differential refractometer, the output current value shown at the position separated every 20 counts between the GPC count number 900 and 1440. (Pi), its G
Molecular weight corresponding to PC count number (based on calibration curve) Mi
Each is calculated as follows.

Next, the weight average molecular weight of VDO-MA in the present invention,
“The number average molecular weight is the molecular weight M calculated in this way.
Using the weight fraction Wt of i and the molecular weight Mi, each is calculated as follows.

Weight average molecular weight = Σ (WtxMi) In addition, the content of copolymers with a molecular weight of 20,000 or less in the present invention is:
Calculate as follows. Add up the weight fractions Wi corresponding to each of Mi with a molecular weight of 20,000 or less, and multiply the total by 100 times,
The copolymer content (weight percent) has a molecular weight of 20,000 or less.

As described above, the method of determining weight average molecular weight and number average molecular weight using the GPC method is widely known in publications related to polymers, such as "Kobonshi Measuring Methods Volume 1" (Baifukansha, 1972). It's a method.

The evaluation method and evaluation scale used in the present invention will be described in detail below.

■ Productivity evaluation in industrial equipment +11 Evaluation using single layer film production equipment.

The outline of the extrusion-film forming method is as follows.

In Fig. 7, extruder ■ (diameter D=80 myn, L=
The raw material resin supplied from the hot section 2 is melted and kneaded in a temperature control zone 5 section), and a circular die 3 (diameter 200 m
m, slit gap 1 trm), 1 per unit time
After extruding the extruded cylindrical film 4 at a rate of 00 Ail and having a target thickness of 1 to a cooling tank 5 and supercooling it, the air sealed in the cylindrical film and the pinch roll 6.6'; ? ,? ' and the peripheral speed ratio between vertical x horizontal (4 to 6
×4 to 6) simultaneous inflation and biaxial stretching,
This is folded into a two-layer flat film 8, and folded onto the winding shaft 10 of the winding device 9 with a thickness of 1200 or 1900 ru.
A two-layered film (40 microns in total) with a wall thickness of n % of 20 microns is wound at a winding speed of 13 or 20 m/7 minutes.

The outline of the evaluation method is as follows.

We prepared a three-shift experimental team made up of workers skilled in VDO-VC film forming experiments and production, and selected important factors as evaluation items for maintaining labor productivity and set quality in continuous production. The contents of these evaluation items were prepared in advance based on an experimental plan that considered whether the content of these evaluation items could be evaluated in the most accurate and efficient manner. Indicate by evaluation.

The evaluation items and evaluation scale are as follows.

a) The purpose was to evaluate the thermal stability of the resin during the extrusion process, and the continuous sustainability of the thermal stability of the resin against stagnation in the extruder. It is evaluated by the length of time during extrusion until it forms on the inner film.

However, the data depends on the actual loss of film production during the target 72 hours, but if decomposed products leak out, film production must be interrupted, the inside of the extruder must be cleaned or disassembled and cleaned, and film production may be continued later. So,
In this case, data on the outflow of decomposed products caused by the interruption time and insufficient cleaning of the extruder at the start-up of film production shall be excluded from the calculations.

Evaluation scale 1, rating i'a symbol Average time until the decomposed product flows out ◎
24 hours or more O: Less than 24 hours to 8 hours or more Δ: Less than 8 hours to 1 hour or more ×: Less than 1 hour b) Puncture rate Continuous sustainability of inflation film formation? This is an evaluation of the rate at which the no-pull is damaged during inflation due to abnormalities other than the decomposed products (for example, air bubbles, outflow of unmelted materials, etc.), expressed as an average unit time. Note that data calculation procedures are in accordance with item a) above.

Evaluation scale, evaluation symbol, average number of occurrences of 9 per hour ◎; 0.1
Less than 0 times; 0-1 times or more to less than 0.3 times Δ; ;0.3
2 or more times to less than 2 times ×; 2 or more times The operation of cutting along the die slit surface at 30 second intervals was continuously repeated to obtain 10 cut extruded pieces, the weight of each piece was accurately measured, and the difference between the maximum and minimum weights was determined.
The ratio to the average weight of the 10 pieces is calculated as a percentage.

Evaluation scale Evaluation symbol: Size of spots: 0 less than 2% 0 2% or more to 4% undropped Δ 4% or more to less than 7% × 7 seconds or more D) Cylindrical extrudate cooled in a cooling tank with 4 spots in the width direction The wall thickness was measured using a micro gauge at 50 points equally spaced in the circumferential direction, and the standard deviation of the thickness variation was calculated and shown.

d) The purpose is to evaluate the uniformity of the thickness in the width direction of a cylindrical extrudate before stretching in four spots in the width direction. After setting the temperature to a temperature intermediate between the temperature at which retention occurs and the temperature at which thermal decomposition of the resin occurs,
Between the slits of the die 18 If I, of course, based on the knowledge of extrusion molding of vinylidene chloride-vinyl chloride copolymer, the era name was adjusted, and the wall thickness of the cylindrical extrudate cooled in the cooling tank was equalized in the circumferential direction. 50 points at intervals, micro gauge (A8TM, o,
374], the standard deviation of the measured thickness at 50 points was calculated using the following formula, and the standard deviation was multiplied by 3.

Here, Xi is each measured thickness, f is the average thickness, n
means the number of measurement points, that is, 50.

Evaluation scale rating symbol 4 Size of spot ◎; Less than 0.05w ○; 0.05 or more ~ less than 0.1 ttrmΔ
; 0.1w1 or more to less than 0.2+o+ x t O-2 or more e) Homogeneous stretchability This is to evaluate the uniformity of the widthwise thickness of the cylindrical film after stretching. After setting the conditions and peripheral speed ratio of the pinch rolls so that a predetermined longitudinal and transverse stretching ratio can be obtained according to the characteristics of each resin, the two-layered film is peeled off again. The thickness of the shaped film was measured at 50 points at equal intervals in the circumferential direction using a dial gauge (A
8TM, D, 374], the standard deviation of the measured thickness at 50 points was calculated using the formula explained in section D), and the standard deviation was multiplied by 3.

Evaluation scale evaluation symbol Float size ◎; Less than 1 micron○; 1 micron or more - less than 2 micronsΔ; 2 microns or more - less than 4 microns ×; 4 microns or more (2) Using five-layer laminated film production equipment evaluation.

The outline of the extrusion-film forming method is as follows.

In FIG. 8, llll resin polypropylene (pp) is melted in each of three extruders 20, 21, and 22.
, ethylene-vinyl acetate copolymer (BVA), vinyl chloride, lidene-methyl acrylate copolymer (VDO)
-MA) to the feed shade block 23, and this part molecule, PP/EVA/YDO-MA/1ifVA/P
Make a resin block-like object laminated in the order of P, and then
It is guided to the die 24 (width 200G+w, slit gap 3), rolled out into a sheet and coextruded, and then passed through the cooling roll group 2.
After cooling at a temperature of 5°25', a film with a width of 1950 mm and a wall thickness of 65 microns [layer structure, PP (20
μ)/EV person (5tt)/VDO-MA (15μ)
/ETA (s μ)/PP (20 μ)] Roll up as the target 5-layer laminated film. [Length L] of the extruder used
) 7 calibers (D)] are each (3120m/100
m+) = 26, (1080m760m)=1
8, (1600m+/80m+)=20, and the target total extrusion amount was set to 2SQkg/Hr.

The outline of the evaluation method is as follows.

An operator skilled in coextrusion film forming experiments using VDO-vo!
For each resin to be tested,
First, after confirming that stable film formation was possible by setting the extrusion temperature at which the above-mentioned five-layer coextruded laminated film could be formed,
An operation to shift the extrusion temperature of VDO-MA by 5 degrees Celsius on both high and low sides centering on the set extrusion temperature (temperature change rate 1
'C/ 1 minute) is repeated to determine the allowable change range of the extrusion temperature that allows the extrusion film to be formed without disturbing the VDO-M five layers in the cross section of the formed film, and approximately within the allowable change temperature. The laminated film formed at the median extrusion temperature was stretched 8 times in the width direction using a tenter (stretching temperature 130°C).
The oxygen permeability of the film before and after stretching (A8TM.

D, 1434) was measured, and the rate of change (rate of improvement and rate of decrease in rear properties) of oxygen permeability (converted to thickness) due to stretching was taken as lamination stretchability.

f) Permissible extrusion temperature change range evaluation symbol: Medium allowable temperature; 20°C or higher ○; Less than 20°C to 10°C or more Δ; Less than 10°C to 5°C or more ×; Less than 5°C g) Lamination stretchability evaluation symbol 4 stretching Improvement rate of rear property depending on ◎; 10
Improvement rate of % or more ○; Improvement rate of 10 incomplete # to 0% Δ; Decrease rate of less than 10% ×; Decrease rate of 10 or more We have considered the following and divided them into the following four stages.

Evaluation symbol ◎: Have sufficient confidence in their intentions in industrial equipment.

○: Possible to produce in industrial equipment by partially changing the design Δ: Unsuitable for production in industrial equipment (somehow impossible for experiments in small equipment) X: Obtaining a molded product The VDO-M human resin used in the difficult experiment and its manufacturing method are as follows.

Capacity 30m containing 11000# water solution containing methylcellulose 11# and ethylenediamine 7.5#
A polymerization raw material prepared by dissolving 15 # of diisopropyl peroxydicasenate in 7500 # of mixed monomers of vinylidene chloride monomer and methyl acrylate monomer (weight ratio 90:10) was loaded into the polymerization vessel No. 3 under reduced pressure, and the mixture was stirred using Fachdler type stirring. M turbidity polymerization was carried out while stirring with a stirrer with blades.The degree of polymerization was determined by starting from 30°C, heating at 30°C for 4 hours, and increasing the temperature to 40°C at a heating rate of 1°C/hour.
After that, polymerization was continued at a heating rate of 1.5°C/hour until 55°C, and the polymerization rate was 97% over a total polymerization time of 24 hours.
A copolymer of (this resin is designated as the resin with symbol ■) was obtained.

The above polymerization conditions (temperature and time) were changed to change the average molecular weight □, and the symbols i, u, tv were prepared in the same manner.

The resins ① and ② were polymerized.

Next, the mixing ratio of vinylidene chloride monomer and methyl acrylate was changed to a weight ratio of 97; 3.92.5; 7.5.85; 15, and two levels of resin with average molecular weight targets of 60,000 and 140,000 were polymerized. The symbols ■, ■, IK, X, M.

It was an eyebrow.

The compositions and properties of the 12 resins produced by polymerization are as shown in Table 1.

Below is an example of Sohaku disaster ~ 1 Table 1, each of the six types of resins with symbols ■ ~
'rfL amount% (both are heat stabilizers) was added and mixed, and using this resin, an experiment was conducted to evaluate productivity in industrial equipment using the single-layer film production equipment described in the text. .

The results are as shown in Table 2. Some resins cannot be stably extruded and the actual jt1 is interrupted, and some resins can be extruded somehow but cannot reach the state of forming a film. In most cases, the evaluation of the possible evaluation items was barely completed.

Just to be sure, we also conducted an evaluation using a five-layer laminated film production facility, but found that only the resin with the symbol m could be used for lamination, so the results were promising. was not obtained. Table 2 summarizes these results.

(Example) Example/Comparative Example ~ 1 2 to 3 ai of the resins with symbols I to ■ in Table 1 above were mixed to create a total of 118 types of mixed resins in A-, and the above experimental examples ~ We repeated the experiment to evaluate productivity in industrial equipment in the same way as in 1 (see Table 3).The results were surprising. It is a fact that by mixing these in appropriate proportions, it becomes a resin that can be produced in industrial equipment.

Table 3 was compiled based on the inventors' hypothesis that the root of the above surprising fact is related to the content of copolymers with a molecular weight of 20,000 or less in VDO-M human flesh. This is an analysis table in which the results of Table 2 (Experimental Example 1) are added to the results of Example/Comparative Example 1, and the whole is evaluated using the comprehensive evaluation scale described in the text.

However, the results in Table 3 do not make clear the regularity of the above hypothesis.

Figure 1 is a more complicated analysis of the results in Table 3. The horizontal axis shows the weight average molecular weight of the resin (logarithmic scale), and the vertical axis shows the weight average molecular weight of the resin (copolymer). Copolymer content with a molecular weight of 20,000 or less ``4 (logarithmic scale) is plotted on the rectangular coordinates, respectively, and the results of the potency evaluation in Table 3 (◎, O9Δ, × mark)
The symbol 1 is plotted as the coordinate point of the copolymer showing the result.

According to Figure 1, it is clear that the technical idea behind the adjustment is to replace the resins that could not be produced with industrial equipment (Δ, those marked with x) with those that are possible (◎, those marked with O). It has become,
The idea is to place the VDO-M resin component at point A (70,000, 180,000, ]
, point B [150,000, 4], point 0 [250,000, 4], point D [1
20,000.

18] is selected and adjusted so that the value is within the range shown by the rectangle formed by connecting the four coordinate points of
), point F (10,50,000, 8], point G [130,000, 8], and point H [100,000, 14] so that the copolymer is within the range of the quadrilateral. This proves a fact.

In addition, these copolymers in the rectangular range of B, F, G, and H have a value of 2 in the value expressed by weight average molecular number ÷ number average molecular weight.
It is also noteworthy that the value is ~2.4.

Examples/Comparative Examples ~2 Six types of resins with symbols 4 to M in Table 1 were evaluated for productivity in industrial equipment equivalent to Experimental Example ~1. The results were similar to those in Experimental Examples 1 to 1, and were in a state that could not be used for production (see Table 4). □ Next, combine 2a or more of the above Vll-M resin and make VDO
-MAO component composition is VDO:MA weight ratio 97:
3.92.5 near, 5.90: 10.85:1
The mixture was adjusted to the ratio shown in Table 4 so that the ratio was 5.95:5. The components and properties of this γ mixed resin are 2X and 3X in Table 4.

fart Shown as resins with symbols 4X, 5X, 6X.

Regarding the 2X to 6X hexapole mixed resins in Table 4, the productivity in industrial equipment was evaluated as described above and in P1. Similar to the results obtained in Examples and Comparative Examples ~ 1, the results showed a surprising phenomenon in which the evaluation of production impossibility changed to that of production possible.According to the results in Table 4, the technology of the present invention The idea is that under a specific range of weight average molecular weight, co-1 with a molecular weight of 20,000 or less in the VDO-MA copolymer
It has been proven that the advantage of adjusting the content of the combined material to fall within the range of 4 to 18% is common and applicable to a wide range of different VDO:MA component ratios.

Below is a margin example ~ 3 The raw material resin of the PP extruder and Ev extruder of the equipment shown in Fig. 8 was changed to all polyethylene (PR), and VDO-MA
2X in Table 4 as the raw material resin for the extruder.

Using VDO-MA 'i shown in aX, 4X, sX, 6X, width 1950W, wall thickness 75 microns [layer structure, PE (
30μ)/VDO-MA(15μ), /PFX(30μ
) ) The target three-layer laminated film was formed and rolled up. The pE layer was peeled off from this three-layer laminated film, and the VDO-M
A single-layer unstretched film was obtained and subjected to evaluation in the experimental diagrams below.

Figures 2 and 3 show VDO-
FIG. 2 is an experimental diagram for evaluating an unstretched film of MA resin.

Figure 4 shows the VDO-M shown in Table 4 02X, 3X, 6X.
A(i'), Figure 5 shows the VDO shown in Table 4 17) 4X
- This is an experimental diagram of evaluation of each unstretched film of MAO1.

Example ~ 4 Using the device sound shown in Fig. 7, the VDO shown in 3X in Table 4
- MA resin was stretched biaxially by inflation to form a two-layered film (40 microns in total) with a vertical and horizontal stretching ratio (6 x 6), a width of 1900, and a wall thickness of 20 microns (40 microns in total), which was subjected to evaluation in the following experimental diagram. .

FIG. 6 is an experimental diagram of a stretched film of VDO-MA resin indicated by 3X in Table 4, which was evaluated.

Figures 2 to 6 are experimental diagrams showing a part of the usefulness of VDO-MA resin film, and the meaning of each diagram is as follows:
A brief explanation will be given in the figure Ill.

First, FIG. 2 shows the VDOiMAO component ratio and 0. TR(
Based on A8TM D 1434 (unit: 15μ・cc
/m" 24Hr-atm ・20℃"6sxRH))
and WVT 几 (based on JIS ZO208 (unit: 1s/
J -97m"-24Hr -40℃・90%uH))
A diagram showing the relationship between Figure 3 shows the relationship between the component ratio of vDC;MA and elemental tear strength based on A8TM1938 (unit -1).
92.5); (3 to 7.5).

According to the results shown in Figure 2.3, the film obtained by the method of the present invention has extremely low oxygen permeability and water vapor permeability, indicating its usefulness as an excellent barrier surface material. In particular, it is noteworthy that VDO-M's inherent barrier properties can be utilized as a result of the film being formed without using plasticizers that inhibit the barrier properties of gold.

This barrier property tends to be better as the amount of MA component in the copolymer is smaller. This tends to impair toughness, and even if it were to be put into practical use by being sandwiched between layers, the amount of MA component would only be around 3% by weight, which would satisfy the lower limit of its practical mechanical properties. It shows that it is difficult.

From the above viewpoint, it can be said that when the content of MA is 3 to 15% by weight, its useful value as a barrier material is extremely high.

FIG. 4 is an example showing the S-8 curve (strain-stress relationship) characteristics of the film obtained according to the present invention. An unstretched film with an MA component amount of toi=% was evaluated and this is shown as a solid line for comparison. The evaluation (broken #) of a VDO-VO film (with a VC component of 13% by weight) under the same stretching conditions is also listed. The measurement conditions are width 10m+, length 150m
Grip the sample piece cut into a circle with a distance of 100 m between the clips, and apply tension until it breaks using a tensile tester (Te/Shiron ■ type; manufactured by Toyo Zeltwin Co., Ltd.) that applies a tensile speed of 300 m/min. This shows a composite of the related trajectories when the gripping clip is returned to the original position at a speed of 1000 groups/min after the gripping clip is further pulled to 100% elongation.

According to the results shown in Figure 4, VD(3-MA (lol)) can be stretched with approximately half the tensile stress compared to vDa -va (broken line), and has an elongation at break t- of more than four times that of vDa -va (broken line). Furthermore, recovery at 100% elongation (dotted chain line)
In this case, the elongation was restored to 15%, indicating that it had characteristics not found in VDO-VO.

Therefore, when utilizing this characteristic and applying it to VDO-MAe stretch film applications, the usefulness of PVC film, which is the current main film, as a material that can be used as a film material is extremely large. I understand.

Furthermore, FIG. 5 shows the heat shrinkability (water immersion method 1 (solid line), and for comparison, the results for a highly shrinkable VDO-VO film (VC component: 17% by weight, 4 times stretched product) are shown as a broken line.

According to the results shown in Figure 5, VDO-MA has higher heat shrinkability over a wide temperature range than VDO-VO, and is expected to be used as low-temperature shrinkable films, high-shrinkable films, etc. I know what I can do. This is true for conventional VDO
When trying to obtain a highly shrinkable laminated film using a resin based resin as a resin layer, the low shrinkage of the vDO resin layer was an obstacle to imparting heat shrinkability to the entire laminated film. On the other hand, 1. It means that it becomes a useful film material that removes this obstacle.

Example ~5 Methylcellulose IIA? , ethylenediamine 7.54
Capacity 30 containing 11000 # of aqueous solution dissolved in
A polymerization raw material obtained by bath dissolving 12 # of diisopropyl peroxydicasenate in 7,000 # of mixed monomer of vinylidene chloride monomer and memory acrylate monomer (weight ratio 90:10) was loaded into a m30 polymerization vessel under reduced pressure, and the mixture was stirred using a Faudler type stirring method. Polymerization was carried out with stirring using a stirrer with blades. The polymerization temperature started at 30°C and increased to 4 at 30°C.
Polymerization was carried out at a rate of temperature increase of 1°C/hour up to 40°C, and then the polymerization was continued at 40°C. When the total polymerization time reached 24 hours, 500% of the mixed monomers at the same weight ratio as above were added.
A polymerization raw material obtained by bath-dissolving 3 # of lauryl peroxide was charged into a polymerization vessel. The polymerization temperature was increased from 40°C to 75°C at a rate of 7°C/hour, and when it reached 75°C, the polymerization was completed, and the polymerization was carried out for a total polymerization time of 29 hours to obtain a copolymer. Ta.

The weight average molecular weight, number average molecular weight, and content of copolymers with a molecular weight of 20,000 or less of the above copolymer were measured by the GPC method described in the text, and the results were 108,000 and 490,116, respectively.
It was kii percent.

The above measurement results show that the copolymer obtained under these polymerization conditions meets the desired target values for the copolymer defined in the present invention.

The above-mentioned copolymer was subjected to an experiment to evaluate productivity under industrial standards using the method described in the text. As a result, all of the evaluation items described in the main text received a mark ◎ on the evaluation scale.

Based on the above results, the technical concept of the present invention, namely, the ability to adjust the content of copolymers with a molecular weight of 20,000 or less in a VDO-M human copolymer with a weight average molecular weight in a specific range to 41% by weight to 41% by weight. This meaning applies when the means to adjust the content of copolymers with a molecular weight of 20,000 or less is not limited to simply mixing the copolymers with each other, but also when adjusting the bundling method and conditions. It has been proven that it is possible.

[Effects of the present invention]

As has been clarified above, the present invention has the above-mentioned configuration, and can be used in VDO-MA extrusion molded metal industry equipment.
This has made it possible to stably supply the product with a quality level that meets market demands.

In addition, the method of the present invention extracts the quality of the YDO-MA material itself, so it has a high level of clearness.
It is highly utilized as a new resin material that exhibits a high level of heat shrinkability or, in some cases, stretchability.

The present invention also provides VDO-
Since this invention gives a single target value to the MA resin composition, it is an excellent invention that will play a large role in industry, such as having a large influence on the future development and improvement of polymerization conditions.

[Brief explanation of drawings]

Figures 1 to 6 are experimental diagrams that clarify the technical contents of the present invention, Figure 1 is an analysis diagram, and Figures 2.3, 4, and 5.6 illustrate the usability of the obtained films. Characteristic diagram shown, Section 7.8
The figure is a conceptual diagram of the device used for evaluation. Patent applicant Asahi Kasei Kogyo Co., Ltd. Figure 1 5, 7 1075507F Weight average molecular weight Figure 2 Large 11 Honaka - MAk [,! Quantity Part Death Figure 3 Common Iji U Honchu, ? Inter AM trap, i heavy percent Fig. 4 3 5 7.5 P-Bogei Chuto HA 8 # 9 weight percent Fig. 5 Fig. 6 Fig. 8

Claims (1)

[Claims] A vinylidene chloride-methyl acrylate copolymer is supplied to an extruder, melt-kneaded, extruded into a desired shape, stretched as necessary, and shaped into a sheet, film or container. In the melt extrusion processing method for vinylidene chloride-methyl acrylate copolymer to be molded, the vinylidene chloride-methyl acrylate copolymer contains:
The MA component is 3 to 15 weight percent based on 100 copolymers, and the weight average molecular weight measured by GPC method (gel permeation chromatography method) is 70,000 to 250,000,
The relationship between the copolymer content with a molecular weight of 20,000 or less (according to the same GPC method) contained in the copolymer is as follows: Point A [70,000, 18], point B [150,000, 4], point C [
Vinylidene chloride-methyl acrylate copolymer adjusted to satisfy the relationship within the range of a quadrilateral formed by connecting the four coordinate points of point D [120,000, 4] and point D [120,000, 18] with straight lines. A method for molding a vinylidene chloride-methyl acrylate copolymer using a melt extrusion method characterized by using coalescence.