JPH10120795A - Measurement of gelation degree of poly(vinyl chloride) and device therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable simple, prompt. reproducible and highly reliable measurement of gelation degree of the subject polymer by determining the angle distribution dependency of scattered light intensity in the light-scattering method. SOLUTION: After a poly(vinyl chloride) molded product (Z) is irradiated with light, the angle distribution dependency of intensity of the light scattered by Z is measured to determine the gelation degree. In an example, Z is irradiated with a monochromic visible light to obtain the dependency on the angle (θ) of the intensity (I) of scattered light from the intercept (A) and the gradient (B), when the square roots of I are plotted to the square of (q) determined from the relationship of the formula: q=(4π/λ)sin(θ/2) where (q) is an angular variable; λ is wavelength), whereby the average particle diameter [d in μm] of the remaining particles in the Z is known from the formula: d=C(A/B)<1/2> (C is the unit constant) and d=1 is defined as G (gelation degree) = 0% and d=0.1 is defined as G=100% and G of Z is obtained from the relation of the formula: G=(1-d)×100.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and a method for easily and quickly measuring the gelation degree of polyvinyl chloride based on the angular distribution dependence of the intensity of scattered light from polyvinyl chloride using a light scattering method. It concerns the device.

[0002]

2. Description of the Related Art Among polyvinyl chlorides, in particular, polyvinyl chlorides prepared by a suspension polymerization method are composed of sub-grains, agglomerates, primary particles, domains in the order of 100 μm to 300 μm outermost particles called grains. , And have a hierarchical particle structure up to the micro domain, and when subjected to molding, the particles are refined as needed by the history of heat and the history of shearing force of the processing machine during molding. However, in the final molded product of polyvinyl chloride, several μm to 0.05 μm which could not be collapsed and refined at the time of molding were formed.
Particles of the order of m remain, and such remaining particles act as structural defects, which may adversely affect physical properties such as material strength characteristics of the molded article.

Conventionally, methods for evaluating the degree of gelation of a molded article of polyvinyl chloride include the following. 1) The degree of gelation is empirically evaluated based on the degree of elasticity of the polyvinyl chloride compound during molding. 2) A method of immersing the molded body in a solvent such as acetone and judging the degree of shape retention of the molded body, 3) Melting of polyvinyl chloride microcrystals melted and recrystallized during molding by the DSC method There is known a method of calculating the degree of gelation from the relative amount ratio between the calorific value and the heat of fusion of unmelted microcrystals.

[0004]

However, both of the above methods 1) and 2) are extremely abstract evaluation scales, and represent not only the problem that the evaluation order differs depending on the operator but also specific numbers. As a result, there has been a problem in reproducibility and reliability. 3)
In the method (1), if the gelation has not progressed much, the amount of the melted and recrystallized microcrystals is too small. In addition, there has been a problem that if gelation proceeds extremely, the amount of unmelted microcrystals is too small to be detected.

Accordingly, an object of the present invention is to provide a measuring method and a measuring apparatus for simply and quickly measuring the degree of gelation of polyvinyl chloride by using a light scattering method instead of such a conventional method. is there.

[0006]

Means for Solving the Problems As a result of intensive studies to solve the above problems, the present inventor has found that the angle distribution dependency of the scattered light intensity obtained by the light scattering method and the degree of gelation are well correlated. And completed the present invention.

That is, the present invention is characterized in that after irradiating a molded article of polyvinyl chloride with light, the degree of gelation is determined from the angle distribution dependence of the scattered light intensity of light scattered from the molded article of polyvinyl chloride. A method for measuring the degree of gelation of polyvinyl chloride, and a light source that emits light of a certain wavelength, a light chopper for irradiating incident light from the light source to the polyvinyl chloride molded article as intermittent light of a certain wavelength, A light scattering measurement device that detects the same wavelength component of the scattered light from the polyvinyl chloride molded product as that cut by the light chopper with a lock-in amplifier, and polyvinyl chloride is obtained from the angle distribution dependence of the scattered light intensity of the scattered light. The present invention relates to an apparatus for measuring the degree of gelation of polyvinyl chloride, comprising an arithmetic processing unit for determining the degree of gelation of polyvinyl chloride.

Hereinafter, the present invention will be described in detail.

The gelation and the degree of gelation of polyvinyl chloride in the present invention means that when polyvinyl chloride is subjected to molding processing, undisintegrated or unmelted residual particles in polyvinyl chloride are kneaded by molding processing. The process of becoming smaller or smaller is called gelation, and the relative degree is called the degree of gelation.

The method and apparatus for measuring the degree of gelation of polyvinyl chloride according to the present invention will be described in detail with reference to the drawings of the light scattering measuring apparatus shown in FIGS. 1 and 2. The present invention is described in the drawings. It is not limited to those that are.

The apparatus shown in FIG. 1 is a side view of one example of the apparatus for measuring the degree of gelation of polyvinyl chloride of the present invention.

The apparatus shown in FIG. 2 is an upper view of one example of the apparatus for measuring the degree of gelation of polyvinyl chloride of the present invention.

In the present invention, the light applied to the polyvinyl chloride molded article is preferably light having a certain wavelength,
It is preferable to use the wavelength properly depending on the size of the residual particles in the polyvinyl chloride. That is, it is possible to use a light source of long wavelength light in the case of a polyvinyl chloride molded article having relatively large residual particles in polyvinyl chloride, and to use a light source of short wavelength light in the case of relatively small residual particles. preferable.

For example, a domain aggregate in which the remaining particles in the polyvinyl chloride are in the range of 0.1 μm to 1 μm in which domains or a plurality of domains are aggregated and aggregated, or a plurality of primary particles or a plurality of primary particles In the case of a residual particle of 0.1 μm to 10 μm such as a primary particle aggregate having a range of 1 μm to 10 μm which is aggregated and aggregated, a visible light source having a wavelength of 0.4 μm to 0.8 μm may be used. preferable. As such a visible light source, for example, a commercially available laser light source can be used, and a helium-neon laser (wavelength: 0.633 μm) manufactured by Uniface Co., Ltd. can be used. Furthermore, the primary particles or 1 μm or
In the case of 10 μm residual particles, an infrared laser having a wavelength of 1 μm or more, a YAG laser, a carbon dioxide laser having a wavelength of 9 to 11 μm, or the like can be used as a light source.
0.01 μm in which residual particles in polyvinyl chloride are microdomains or a plurality of microdomains are aggregated and aggregated
In the case of 0.01 μm to 0.1 μm residual particles such as microdomain aggregates in the range of 0.1 μm to 0.1 μm, a short-wavelength laser having a wavelength of less than 0.4 μm, an excimer laser, or the like can be used.

Further, in the present invention, when determining the dependence of the scattered light intensity on the angular distribution, when using an apparatus in which each optical member is not stored in a container such as a dark box for blocking stray light from outside and noise light, Alternatively, it is preferable to use a light chopper and a lock-in amplifier together in order to suppress the adverse effect of the noise light. By using a light chopper and a lock-in amplifier together, the light chopper divides the incident light to a specific frequency, irradiates the polyvinyl chloride molded article as intermittent light, and locks only the light of a specific frequency component into the lock-in amplifier. , The intensity of scattered light from the polyvinyl chloride molded article alone is increased by removing noise without being affected by stray light due to multiple reflections or external noise light, etc. ) The ratio can be actually measured, and the measurement accuracy can be improved.

A commercially available light chopper may be used as long as it can fix the frequency. The lock-in amplifier can also achieve the object of the present invention using a commercially available lock-in amplifier. For example, a lock-in amplifier manufactured by NF Circuit Design Block Co., Ltd. can be used.

Further, as a receiver for the scattered light from the polyvinyl chloride molded article, for example, a photodiode, a photomultiplier called a photomultiplier, a light counter, or the like can be used to measure the scattered light intensity. is there. And
When the residual particles in the polyvinyl chloride are large and the scattered light intensity is high, a photodiode is suitable. On the other hand, when the particle structure is small and the scattered light intensity is low, a photomultiplier or a light counter is suitable.

The turntable on which the light receiver is mounted is 0 ° to 1 °.
It is preferable that the angle can be set every 0.1 ° up to 80 °, and a manual turntable or an automatic turntable driven by a pulse motor can be used.

In the present invention, the range in which the angle distribution dependence of the scattered light intensity is measured is such that the residual particles in the polyvinyl chloride molded article are primary particles of polyvinyl chloride or aggregates thereof.
1 ° to 20 ° is preferred, and the angle range of 5 ° to 50 ° is preferred in the case of polyvinyl chloride domains or aggregates finer than the primary particles. Furthermore, in the case of fine polyvinyl chloride microdomains or agglomerates thereof, 30 ° to 70 ° C
゜ is suitable.

In the present invention, the degree of gelation of polyvinyl chloride is determined by irradiating the polyvinyl chloride molded article with light and then determining the angle distribution dependence of the scattered light intensity of the light scattered from the polyvinyl chloride molded article. Can be evaluated.

For example, when the angle variable q relating to the scattered light intensity I and the scattering angle θ is q = (4π / λ) sin (θ / 2), 1) the scattered light intensity I is plotted against the angle variable q ( Hereinafter, this is referred to as plot 1. FIG. 3) A method of evaluating the degree of gelation from the positional relationship of plots obtained from polyvinyl chloride molded articles having different heat histories and shearing histories during molding, 2) Angle A method of plotting the reciprocal of the square root of the scattered light intensity I with respect to the square of the variable q (hereinafter referred to as plot 2; FIG. 4) and evaluating the gelation degree from the positional relationship, 3) a straight line in plot 2 Is obtained, the average particle diameter is calculated using a statistical analysis method from the slope and the intercept,
A method of evaluating the degree of gelation based on the magnitude relation may be used. It is also possible to statistically calculate the size of the remaining particles by converting the scattered light intensity I and the angle variable q into appropriate functions.

In the method for evaluating the degree of gelation using the plot 1 as in the above 1), the scattered light intensity I increases as the average particle diameter of the residual particles in the polyvinyl chloride increases or as the residual particles increase. And the angle distribution dependence, that is, the dependence of the scattered light intensity I on the angle variable q is large, which is reflected in the plot. Therefore, a scattered light intensity spectrum in which the scattered light intensity I sharply decreases from a large value is obtained in a molded body sample in which gelation has not progressed.

In the method of evaluating the degree of gelation using the plot 2 as in the above 2) and 3), a straight line is obtained in the plot 2 and the degree of gelation can be evaluated from the positional relationship. As the size of the residual particles in the polyvinyl chloride is larger, the slope of plot 2 is larger, and the gelation does not progress and the gelation degree is lower. Also, as the number of residual particles in polyvinyl chloride increases, the intercept of plot 2 becomes smaller, and in this case, too, gelation does not progress and the degree of gelation is low.

Further, according to the method described in “Polymer Alloy” Kyoritsu Shuppan, for example, the intercept A and the slope B of the plot 2 are plotted.
The average particle diameter corresponding to the size of the residual particles in the polyvinyl chloride can be determined from the following equation (1) based on the apparatus constant C and the apparatus constant C.

Average particle size = C × (B / A) ^1/2 (1) The method of relative evaluation of the degree of gelation using the percentage in the present invention is arbitrary. For example, when the above plot 1 is used,
The upper limit of the position of the spectrum can be used as a measure of the degree of gelation. When the above plot 2 is used, the upper limit and the lower limit of the measured residual particle diameter are set to 0 to 100%, respectively, so that a relative evaluation between them can be made. Furthermore, the range of the absolute value of the measured residual particle diameter is arbitrary, but for example, the average particle diameter of the residual particles calculated by the above equation (1) is 1
The gelation degree is 0%, the average particle diameter is 0.1 μm, the gelation degree is 100%, and the relative evaluation is performed linearly at regular intervals and converted into percentages. )
It can be evaluated as an expression.

Gelation degree (%) = (1−average particle diameter (μm)) × 100 (2) When the absolute value of the residual particles of polyvinyl chloride is quantified and converted into the gelation degree, the particles must be prepared in advance. It is preferable to determine the device constant of the measuring device using a standard sample such as polystyrene latex having a clear diameter and a monodispersed particle size distribution.

In the method and apparatus for measuring the degree of gelation of polyvinyl chloride according to the present invention, when measuring the degree of gelation of polyvinyl chloride from the angular distribution dependence of the scattered light intensity of scattered light, It is preferable to use an arithmetic processing device that has been programmed to calculate the degree of gelation from the angular distribution dependence of the scattered light intensity.

Examples of the polyvinyl chloride which can be used in the present invention include polyvinyl chloride, ethylene-vinyl chloride copolymer, vinyl acetate-vinyl chloride copolymer and the like. Furthermore, various compounding agents such as a stabilizer, a lubricant, and a plasticizer which are usually added to polyvinyl chloride may be added as long as they do not adversely affect the scattering spectrum.

[0029]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples.

Example 1 A helium-neon laser 2a having a wavelength of 0.633 μm (HN-550P, manufactured by Nippon Kagaku Engineering Co., Ltd.) was used as a light source, and a light chopper 5a for converting light from the light source into intermittent light. , Scattered light intensity measuring light receiver 1
0, lock-in amplifier 11 (manufactured by NF Circuit Design Block Co., Ltd., trade name: single phase lock-in amplifier 5)
600), a detector goniometer 8a (manufactured by Nippon Kagaku Engineering Co., Ltd.), a goniometer driving pulse motor controller 8b (manufactured by Nippon Kagaku Engineering Co., Ltd.), a quarter-wave plate 3, a Gram-Thompson-type polarizing element 4 , Sample holding stage 6, pinhole 9, measurement control and personal computer 12 for analysis of angle distribution dependence of scattered light intensity and residual particle diameter in polyvinyl chloride and gel of polyvinyl chloride from angle distribution dependence of scattered light intensity An apparatus for measuring the degree of gelation of polyvinyl chloride comprising an arithmetic processing unit 14 for calculating the degree of conversion was prepared. Here, the arithmetic processing unit 14 plots the reciprocal of the square root of the scattered light intensity I with respect to the square of the angle variable q (plot 2) among the angular distribution dependence of the scattered light intensity analyzed by the personal computer 12. The intercept and inclination at the time are read, and the average particle diameter of the dispersed particles is calculated from the apparatus constant and the above (1). Further, the average particle diameter of the dispersed particles is 1 μm, the gelation degree is 0%, and the average particle diameter is 0.1 μm. This is an arithmetic processing unit in which the degree of gelation is set to 100% and programming for calculating the degree of gelation from the above equation (2) is performed.

FIG. 1 shows a side view of a light scattering measuring device for measuring the gelation degree of polyvinyl chloride.

FIG. 2 shows an upper view of a light scattering measuring device for measuring the gelation degree of polyvinyl chloride.

The apparatus constant C of the measuring apparatus determined by using a polystyrene latex having an average particle diameter of 0.1 μm as a standard sample was 225 [nm ⁻¹ ].

Example 2 Polyvinyl chloride resin (manufactured by Taiyo PVC Co., Ltd., trade name: TH-
1000) 100 parts by weight, stabilizer (manufactured by Nitto Kasei Co., Ltd.)
A polyvinyl chloride resin composition containing 4 parts by weight of N2000E) was kneaded with an 8-inch test roll set at 140 ° C. for 10 minutes to obtain a 1.1-mm thick translucent plate-like molded product. This plate-shaped molded product was molded into a transparent plate-shaped molded product having a thickness of 1.0 mm using a press molding machine set at 140 ° C.

Using the measuring device of Example 1, the scattered light intensity for 10 seconds at each scattering angle was set at 0.5 ° for each scattering angle in the range of 10 ° to 40 °. And the scattered light intensity I was determined.

FIG. 3 shows a plot 1 in which the scattered light intensity I is actually measured against the angle variable q.

FIG. 4 shows a plot 2 in which the reciprocal of the square root of the scattered light intensity I is converted into a Debye plot type with respect to the square of the angle variable q.

Further, the intercept and the slope of the Debye plot of FIG. 4 are read, and the apparatus constant C and the apparatus for measuring the degree of gelation of polyvinyl chloride described in Example 1 having an arithmetic processing unit programmed with the above equation (1). The average particle diameter of the residual particles obtained from was 0.35 μm.

The degree of gelation obtained from the apparatus for measuring the degree of gelation of polyvinyl chloride described in Example 1 was 65.
%Met.

Example 3 A polyvinyl chloride resin composition having the same composition as in Example 2
The mixture was kneaded with an 8-inch test roll set at 85 ° C. for 5 minutes to obtain a 1.1-mm thick translucent plate-like molded product. This plate-like molded body was formed into a transparent plate-like molded body having a thickness of 1.0 mm by using a pressure press molding machine set at 185 ° C.

The same measurement as in Example 2 was performed on the obtained plate-like molded body.

FIG. 3 shows a plot 1 in which the scattered light intensity I is plotted with respect to the angle variable q.

FIG. 4 shows a plot 2 in which the reciprocal of the square root of the scattered light intensity I is converted into a Debye plot type with respect to the square of the angle variable q.

Further, the intercept and inclination of the Debye plot in FIG. 4 were read, and the apparatus constant C and the apparatus for measuring the gelation degree of polyvinyl chloride described in Example 1 having an arithmetic processing unit programmed with the above equation (1) were used. The average particle diameter of the obtained residual particles was 0.26 μm.

Further, the gelation degree obtained from the apparatus for measuring the gelation degree of polyvinyl chloride described in Example 1 is 74.
%Met.

[0046]

According to the method and apparatus for measuring the degree of gelation of polyvinyl chloride of the present invention, the degree of gelation of polyvinyl chloride can be determined simply, quickly and accurately.

[Brief description of the drawings]

FIG. 1 is a side view of an example of an apparatus for measuring the degree of gelation of polyvinyl chloride according to the present invention.

FIG. 2 is an upper view of an example of the apparatus for measuring the degree of gelation of polyvinyl chloride according to the present invention.

FIG. 3 is a plot 1 in which the scattered light intensity I obtained in Examples 2 and 3 is actually measured and plotted against an angle variable q.

FIG. 4 is a plot 2 in which the reciprocal of the square root of the scattered light intensity I obtained in Examples 1 and 2 is converted into a Debye plot type with respect to the square of the angle variable q.

[Explanation of symbols]

1: Optical bench 2a: Helium-neon laser 2b: Stabilized power supply for laser output 3: Quarter-wave plate 4: Gram-Thompson-type polarizing element 5a: Light chopper (frequency 280 Hz) 5b: Light chopper frequency controller 6: Sample Holding stage 7: Sample 8 a: Goniometer for rotating the receiver 8 b: Pulse motor controller for driving the goniometer 9: Pinhole 10: Receiver for measuring scattered light intensity 11: Lock-in amplifier 12: Personal computer for measurement control and data analysis 13 : Scattering angle θ 14: Arithmetic processing unit 15: Angle variable q 16: Scattered light intensity I 17: Square of angle variable q 18: Reciprocal of square root of scattered light intensity I

Claims (4)

[Claims] 1. After irradiating light to a polyvinyl chloride molded article,
A method for measuring the degree of gelation of polyvinyl chloride, wherein the degree of gelation is determined based on the angular distribution dependence of the scattered light intensity of light scattered from the polyvinyl chloride molded article. 2. The polyvinyl chloride according to claim 1, wherein the degree of gelation is determined by converting the angle distribution dependency of the scattered light intensity according to claim 1 into a relative scale using percentage. Method for measuring the degree of gelation. 3. The residual particle diameter of polyvinyl chloride present in the polyvinyl chloride molded article is further determined from the angle distribution dependence of the scattered light intensity according to claim 1, and the residual particle diameter is used as a percentage. The method for measuring the degree of gelation of polyvinyl chloride according to claim 1, wherein the degree of gelation is determined by converting the degree of gelation into a relative scale. 4. A light source for emitting light of a certain wavelength, a light chopper for irradiating incident light from the light source as intermittent light of a certain wavelength onto the polyvinyl chloride molded article, and a light chopper for scattered light from the polyvinyl chloride molded article. A light scattering measurement device that detects the same wavelength component as that cut by the light chopper with a lock-in amplifier, and a calculation process to determine the gelation degree of polyvinyl chloride from the angular distribution dependence of the scattered light intensity of the scattered light An apparatus for measuring the degree of gelation of polyvinyl chloride, comprising an apparatus.