CN102156147A - Method for detecting film forming stability of polypropylene in bidirectional stretching by using thermal analysis method - Google Patents

Abstract

The invention discloses a method for detecting film forming stability of polypropylene in bidirectional stretching by using a thermal analysis method. The method is characterized by comprising the following steps of: preparing polypropylene resin into a thermal analysis test standard sample; performing heating and cooling scanning on the polypropylene by using a differential scanning calorimeter (DSC), and detecting crystallization and melting behavior parameters of the polypropylene material; then designing a thermal treatment program of the polypropylene material according to the crystallization and melting behavior parameters of the material; and performing multi-step thermal treatment on the material, and analyzing the film forming stability when the polypropylene resin is processed by analyzing the results obtained by thermal grading treatment and using calculation of thickness and molecular structure parameters of a polypropylene wafer. The method timely provides film forming stability information of the polypropylene for production and application, and is simple, convenient, quick, efficient and strong in accuracy.

Description

Detect the one-tenth membrane stability of polypropylene in two-way stretch with heat analysis method

Technical field

The present invention relates to detect the one-tenth membrane stability of polypropylene in two-way stretch with heat analysis method, specifically use differential calorimetric scanner (DSC), by the hot stepped thermal treatment of substep, detect the method for Biaxially oriented polypropylene resin one-tenth membrane stability in process of production, belong to the representational field of macromolecular material.

Background technology

In recent years, the biaxial stretching film polypropylene increases fast in the application of packaging field.Along with the development of production technology, require the rate of extension of film more and more faster in the production run, this just requires the one-tenth membrane stability of acrylic resin also to become better and better.If the quality of polypropylene material does not reach the appointment requirement, problems such as rupture of membranes, surface irregularity will appear aborning, influence economic benefit.

At present, the method that characterizes the one-tenth membrane stability of acrylic resin in the biaxial stretching film production is very limited, and has more shortcoming.The general method that adopts has only the test of dimethylbenzene room temperature solvend, but this method is more coarse, can only be inaccurate as a simple criterion; Another kind method is that acrylic resin is test-manufactured on large-scale production plant, but this method cost is high, and needs a large amount of resins, is difficult to provide for practical application and commercial production the information of fast characterizing resin film forming situation.Therefore, be badly in need of a kind of acrylic resin of predicting comparatively simply, efficiently in actual applications and become the method for testing of membrane stability.

Summary of the invention

The objective of the invention is provides with the one-tenth membrane stability of heat analysis method detection polypropylene in two-way stretch at the deficiencies in the prior art, be characterized in that this method is easy to use, fast, detect the one-tenth membrane stability of acrylic resin in the biaxial stretching film production run accurately and efficiently, obtain the structural information of acrylic resin, thereby the prediction polypropylene becomes membrane stability.

Purpose of the present invention is realized by following technical measures

Detecting the one-tenth membrane stability of polypropylene in two-way stretch with heat analysis method may further comprise the steps:

(1) acrylic resin is made the hot analytical test standard model of thickness homogeneous;

(2) acrylic resin is carried out heat and analyzes the heating and cooling scan process, obtain the crystallization and the melting behavior parameter of material:

Sample is stopped 2～7min down for 180～210 ℃ in temperature, to eliminate any residual thermal history, then, reduce to 25～50 ℃ with the rate of temperature fall of 7～12 ℃/min, stop 1～5min, heating rate with 7～12 ℃/min is heated to 180～210 ℃, record decrease temperature crystalline curve and intensification melting curve;

Obtain the Tc T of material from the decrease temperature crystalline curve _c, crystallization onset temperature T _ConsetWith crystallization final temperature T _Cendset, obtain the fusing point T of material from the intensification melting curve _m, melt initiation temperature degree T _Monset, fusion final temperature T _MendsetWith relative crystallinity X _c

(3) heat treatment process of hot classification:

Above-mentioned sample is stopped 2～7min down for 180～210 ℃ in temperature, to eliminate any residual thermal history, then, reduce to 25～50 ℃ with the rate of temperature fall of 5～20 ℃/min, stop 1～5min, be heated to first spontaneous nucleation-annealing temperature T with the heating rate of 5～20 ℃/min _S1=164～170 ℃, stop t _s=5～40min is cooled to 25～50 ℃ with the speed of 5～20 ℃/min, stops 1～5min; Continue to be heated to second spontaneous nucleation-annealing temperature T _S2=160～163 ℃, stop t _s=5～40min is cooled to 25～50 ℃ with the speed of 5～20 ℃/min, stops 1～5min; Heating rate with 5～20 ℃/min is warming up to the 3rd spontaneous nucleation-annealing temperature T _S3=155～159 ℃, stop t _s=5～40min, so, handle, sample is heat-treated under the spontaneous nucleation-annealing temperature that reduces successively by continuous heating and cooling, each spontaneous nucleation-annealing temperature is than the low △ T=2 of a last spontaneous nucleation temperature～7 ℃, as sample spontaneous nucleation-annealing temperature T in the end _Sn=135～142 ℃ stop t down _sBehind=5～40min, be cooled to 25～50 ℃, stop 1～5min, be warming up to 180～210 ℃, write down final melting curve with the heating rate of 5～20 ℃/min;

(4) the hot hierarchical test result to material carries out mathematics match and Theoretical Calculation, analyzes the stability of polypropylene material when the stretching film forming:

A. the calculating of each melting peak relative content

Use professional swarming process of fitting treatment software that final melting curve is carried out the swarming process of fitting treatment, curve is separated into melting peak independent of each other, and calculate the fusing point and the relative content at each peak;

B. the calculating of wafer thickness distribution curve

Calculate the pairing wafer thickness of each melting peak of hot grading curve, and then the wafer thickness distribution situation of calculating acrylic resin, utilize Thomson-Gibbs equation (1) to calculate the pairing wafer thickness L of each melting peak of hot grading curve, and then calculate the wafer thickness distribution situation of acrylic resin:

$T_m={T_m}^0(1-\frac{2\mathrm{\σ}}{\mathrm{\Δ}{H}_{0}L})---\left(1\right)$

In the formula, T _mBe polyacrylic melt temperature, T _m ⁰Be polyacrylic equilibrium melting point, △ H ₀Be polyacrylic melting enthalpy, σ is polyacrylic surface free energy;

C. the calculating of wafer thickness distribution parameter

(2) formula of use and (3) formula are calculated the number average wafer thickness L of material respectively _nWith weight average wafer thickness L _w, use (4) formula to calculate the wafer thickness distribution coefficient I of material:

$L_n=\frac{n_1{\mathrm{<figure-callout\; id="1"\; label="L"\; filenames="HDA0000049116180000011.png,HDA0000049116180000012.png"\; state="\{\{state\}\}">L</figure-callout>}}_1+n_2{L}_2+n_3{L}_3+n_4{\mathrm{<figure-callout\; id="4"\; label="L"\; filenames="HDA0000049116180000011.png,HDA0000049116180000012.png"\; state="\{\{state\}\}">L</figure-callout>}}_4+,K,+n_j{L}_{\mathrm{<figure-callout\; id="1"\; label="j\; n"\; filenames="HDA0000049116180000011.png,HDA0000049116180000012.png"\; state="\{\{state\}\}">j</figure-callout>}}}{n_{}}=\mathrm{\&Sigma;}{f}_i{L}_i---\left(2\right)$

$L_w=\frac{n_1{{\mathrm{<figure-callout\; id="1"\; label="L"\; filenames="HDA0000049116180000011.png,HDA0000049116180000012.png"\; state="\{\{state\}\}">L</figure-callout>}}_1}^2+n_2{{\mathrm{<figure-callout\; id="2"\; label="L"\; filenames="HDA0000049116180000011.png,HDA0000049116180000012.png"\; state="\{\{state\}\}">L</figure-callout>}}_2}^2+n_3{{\mathrm{<figure-callout\; id="3"\; label="L"\; filenames="HDA0000049116180000011.png,HDA0000049116180000012.png"\; state="\{\{state\}\}">L</figure-callout>}}_3}^2+n_4{{\mathrm{<figure-callout\; id="4"\; label="L"\; filenames="HDA0000049116180000011.png,HDA0000049116180000012.png"\; state="\{\{state\}\}">L</figure-callout>}}_4}^2+,K,+n_j{L_j}^2}{n_1{\mathrm{<figure-callout\; id="1"\; label="L"\; filenames="HDA0000049116180000011.png,HDA0000049116180000012.png"\; state="\{\{state\}\}">L</figure-callout>}}_1+n_2{\mathrm{<figure-callout\; id="2"\; label="L"\; filenames="HDA0000049116180000011.png,HDA0000049116180000012.png"\; state="\{\{state\}\}">L</figure-callout>}}_2+n_3{\mathrm{<figure-callout\; id="3"\; label="L"\; filenames="HDA0000049116180000011.png,HDA0000049116180000012.png"\; state="\{\{state\}\}">L</figure-callout>}}_3+n_4{\mathrm{<figure-callout\; id="4"\; label="L"\; filenames="HDA0000049116180000011.png,HDA0000049116180000012.png"\; state="\{\{state\}\}">L</figure-callout>}}_4+,...,+n_j{L}_j}=\frac{\mathrm{\&Sigma;}{f}_i{L_i}^2}{\mathrm{\&Sigma;}{f}_i{L}_i}---\left(3\right)$

$I=\frac{L_w}{L_n}---\left(4\right)$

Wherein, L ₁, L ₂... L _jBe the wafer thickness of melting peak, n ₁, n ₂... n _jIt is the relative percentage composition of melting peak area;

In addition, directly using (1) formula to carry out homogenization to hot classification melting curve handles, obtain the distribution curve of the wafer thickness of each sample that can quantitative comparison, thereby the unevenness of molecular structure regularity is reflected, and then according to the one-tenth membrane stability quality of interpretation of result acrylic resin.

Performance test

Adopt thermoanalysis technology to detect the one-tenth membrane stability of polypropylene in two-way stretch, testing result sees for details shown in Fig. 1-3 and table 1～6, the result shows: from PP-1 to PP-5, on hot grading curve, the relative content at high-temperature fusion peak reduces gradually, and the relative content at middle watery fusion peak raises gradually, the average wafer thickness of resin reduces gradually, show that from PP-1 to PP-5 the high isotacticity component relative content of resin descends gradually, rise gradually than the relative content of low grade component.Because high low grade component concentration changes, the resin wafer thickness descends, and becomes membrane stability progressively to rise, and the rupture of membranes rate reduces gradually.The result of this hot analyzing detecting method is consistent with the testing result of large-scale membrane equipment.

Description of drawings

Fig. 1 .a is the DSC decrease temperature crystalline curves of 5 kinds of isotactic polypropylene samples under example 1 hot classification procedure.

Fig. 1 .b is the DSC intensification melting curves of 5 kinds of isotactic polypropylene samples under example 1 hot classification procedure.

Fig. 2 is the hot classification melting curves of 5 kinds of isotactic polypropylene samples under example 1 hot classification procedure.

Fig. 3 is the wafer thickness distribution curves of 5 kinds of isotactic polypropylene samples under example 1 hot classification procedure.

Embodiment

Below by embodiment the present invention is carried out concrete description, be necessary to be pointed out that at this present embodiment only is used for the present invention is further specified, can not be interpreted as limiting the scope of the invention.The person skilled in the art in this field can make some nonessential improvement and adjustment to the present invention according to the content of the invention described above.

Embodiment 1

Detecting the one-tenth membrane stability of polypropylene in two-way stretch with heat analysis method may further comprise the steps:

1. laboratory sample: five have different molecular structures and the isotactic polypropylene that becomes membrane stability, are numbered PP-1, PP-2, PP-3, PP-4, PP-5.Five kinds of acrylic resins are tested on large-scale membrane machine, and the result shows that from PP-1 to PP-5, the rupture of membranes rate of resin reduces gradually, becomes membrane stability to become better and better.

2. sample is pressed into the thin plate of thickness homogeneous with compression molding forming machine, preparation heat is analyzed the special test sample.

3. sample is stopped 2min down for 180 ℃ in temperature, then, reduce to 25 ℃ with the rate of temperature fall of 7 ℃/min, stop 1min, heating rate with 7 ℃/min is heated to 180 ℃ with sample, and record decrease temperature crystalline curve and intensification melting curve the results are shown in Figure 1.a and Fig. 1 .b;

Obtain the Tc T of material from Fig. 1 .a _c, crystallization onset temperature T _ConsetWith crystallization final temperature T _Cendset, obtain the fusing point T of material from Fig. 1 .b _m, melt initiation temperature degree T _Monset, fusion final temperature T _MendsetWith relative crystallinity X _c

4. above-mentioned sample is stopped 2min down 180 ℃ of temperature, then, reduce to 25 ℃, stop 1min, be heated to first spontaneous nucleation-annealing temperature T with the heating rate of 5 ℃/min with the rate of temperature fall of 5 ℃/min _S1=163 ℃, stop t _s=5min is cooled to 25 ℃ with the rate of temperature fall of 5 ℃/min, stops 1min; Continue to be heated to second spontaneous nucleation-annealing temperature T _S2=160 ℃, stop t _s=5min is cooled to 25 ℃ with sample, stops 1min; Heating rate with 5 ℃/min is warming up to the 3rd spontaneous nucleation-annealing temperature T _S3=157 ℃, stop t _s=5min so, handles by continuous heating and cooling, and sample is heat-treated under the spontaneous nucleation-annealing temperature that reduces successively, and each spontaneous nucleation-annealing temperature is than low △ T=3 ℃ of a last spontaneous nucleation temperature, as sample spontaneous nucleation-annealing temperature T in the end _Sn=136 ℃ stop t down _sBehind=the 5min, be cooled to 25 ℃, stop 1min, be warming up to 180 ℃ with the heating rate of 5 ℃/min, write down final melting curve, experimental result is seen Fig. 2;

5. the hot hierarchical test result to material carries out mathematics match and Theoretical Calculation, analyzes the stability of polypropylene material when the stretching film forming:

A. the calculating of each melting peak relative content

Use professional swarming process of fitting treatment software that final melting curve is carried out the swarming process of fitting treatment, curve is separated into melting peak independent of each other, and calculates the fusing point and the relative content at each peak, swarming the results are shown in table 1;

B. the calculating of wafer thickness distribution curve

Calculate the pairing wafer thickness of each melting peak of hot grading curve, and then the wafer thickness distribution situation of calculating acrylic resin, utilize Thomson-Gibbs equation (1) to calculate the pairing wafer thickness L of each melting peak of hot grading curve, and then calculate the wafer thickness distribution situation of acrylic resin:

$T_m={T_m}^0(1-\frac{2\mathrm{\&sigma;}}{\mathrm{\&Delta;}{H}_{0}L})---\left(1\right)$

In the formula, T _mBe polyacrylic melt temperature, polyacrylic equilibrium melting point T _m ⁰=460K, polyacrylic melting enthalpy △ H ₀=184 * 10 ⁶J/m ³, polyacrylic surface free energy σ=0.0496J/m ²

C. the calculating of wafer thickness distribution parameter

(2) formula of use and (3) formula are calculated the number average wafer thickness L of material respectively _nWith weight average wafer thickness L _w, use (4) formula to calculate the wafer thickness distribution coefficient I of material, experimental result is listed in table 2:

$L_n=\frac{n_1{\mathrm{<figure-callout\; id="1"\; label="L"\; filenames="HDA0000049116180000011.png,HDA0000049116180000012.png"\; state="\{\{state\}\}">L</figure-callout>}}_1+n_2{L}_2+n_3{L}_3+n_4{\mathrm{<figure-callout\; id="4"\; label="L"\; filenames="HDA0000049116180000011.png,HDA0000049116180000012.png"\; state="\{\{state\}\}">L</figure-callout>}}_4+,K,+n_j{L}_{\mathrm{<figure-callout\; id="1"\; label="j\; n"\; filenames="HDA0000049116180000011.png,HDA0000049116180000012.png"\; state="\{\{state\}\}">j</figure-callout>}}}{n_{}}=\mathrm{\&Sigma;}{f}_i{L}_i---\left(2\right)$

$L_w=\frac{n_1{{\mathrm{<figure-callout\; id="1"\; label="L"\; filenames="HDA0000049116180000011.png,HDA0000049116180000012.png"\; state="\{\{state\}\}">L</figure-callout>}}_1}^2+n_2{{\mathrm{<figure-callout\; id="2"\; label="L"\; filenames="HDA0000049116180000011.png,HDA0000049116180000012.png"\; state="\{\{state\}\}">L</figure-callout>}}_2}^2+n_3{{\mathrm{<figure-callout\; id="3"\; label="L"\; filenames="HDA0000049116180000011.png,HDA0000049116180000012.png"\; state="\{\{state\}\}">L</figure-callout>}}_3}^2+n_4{{\mathrm{<figure-callout\; id="4"\; label="L"\; filenames="HDA0000049116180000011.png,HDA0000049116180000012.png"\; state="\{\{state\}\}">L</figure-callout>}}_4}^2+,K,+n_j{L_j}^2}{n_1{\mathrm{<figure-callout\; id="1"\; label="L"\; filenames="HDA0000049116180000011.png,HDA0000049116180000012.png"\; state="\{\{state\}\}">L</figure-callout>}}_1+n_2{\mathrm{<figure-callout\; id="2"\; label="L"\; filenames="HDA0000049116180000011.png,HDA0000049116180000012.png"\; state="\{\{state\}\}">L</figure-callout>}}_2+n_3{\mathrm{<figure-callout\; id="3"\; label="L"\; filenames="HDA0000049116180000011.png,HDA0000049116180000012.png"\; state="\{\{state\}\}">L</figure-callout>}}_3+n_4{\mathrm{<figure-callout\; id="4"\; label="L"\; filenames="HDA0000049116180000011.png,HDA0000049116180000012.png"\; state="\{\{state\}\}">L</figure-callout>}}_4+,...,+n_j{L}_j}=\frac{\mathrm{\&Sigma;}{f}_i{L_i}^2}{\mathrm{\&Sigma;}{f}_i{L}_i}---\left(3\right)$

$I=\frac{L_w}{L_n}---\left(4\right)$

Wherein, L ₁, L ₂... L _jBe the wafer thickness of melting peak, n ₁, n ₂... n _jIt is the relative percentage composition of melting peak area;

In addition, directly using (1) formula to carry out homogenization to hot classification melting curve handles, obtain the distribution curve of the wafer thickness of each sample that can quantitative comparison, thereby the unevenness of molecular structure regularity is reflected, and then according to the one-tenth membrane stability quality of interpretation of result acrylic resin.The results are shown in Figure 3.

From the result of table 1, Fig. 2 as can be seen, from PP-1 to PP-5, on the hot grading curve of sample, the relative content at high-temperature fusion peak reduces gradually, and the content at inferior high-temperature fusion peak increases gradually, from table 2, Fig. 3 as can be seen, from PP-1 to PP-5, the content of thicker wafer reduces gradually, increases gradually than the content of LED reverse mounting type, average wafer thickness diminishes, and it is big that the wafer thickness profile exponent becomes.Above result shows, from PP-1 to PP-5, and the decline of high isotacticity component concentration, the resin wafer thickness descends, and hence one can see that, and in process, from PP-1 to PP-5, the one-tenth membrane stability of acrylic resin progressively rises, and the rupture of membranes rate reduces gradually.This result is consistent with the test result of large-scale film balance.

Embodiment 2

Detecting the one-tenth membrane stability of polypropylene in two-way stretch with heat analysis method may further comprise the steps:

1. laboratory sample: five have different molecular structures and the isotactic polypropylene that becomes membrane stability, are numbered PP-1, PP-2, PP-3, PP-4, PP-5.Five kinds of acrylic resins are tested on large-scale membrane machine, and the result shows that from PP-1 to PP-5, the rupture of membranes rate of resin reduces gradually, becomes membrane stability to become better and better.

2. sample is pressed into the thin plate of thickness homogeneous with compression molding forming machine, preparation heat is analyzed the special test sample.

3. sample is stopped 7min down 210 ℃ of temperature, then, reduce to 50 ℃, stop 5min, sample is heated to 210 ℃, record decrease temperature crystalline curve and intensification melting curve with the heating rate of 12 ℃/min with the rate of temperature fall of 12 ℃/min;

Obtain the Tc T of material from crystallization curve _c, crystallization onset temperature T _ConsetWith crystallization final temperature T _Cendset, obtain the fusing point T of material from melting curve _m, melt initiation temperature degree T _Monset, fusion final temperature T _MendsetWith relative crystallinity X _c

4. above-mentioned sample is stopped 7min down 210 ℃ of temperature, then, reduce to 50 ℃, stop 5min, be heated to first spontaneous nucleation-annealing temperature T with the heating rate of 20 ℃/min with the rate of temperature fall of 20 ℃/min _S1=170 ℃, stop t _s=40min is cooled to 50 ℃ with the speed of 20 ℃/min, stops 5min; Continue to be heated to second spontaneous nucleation-annealing temperature T _S2=163 ℃, stop t _s=40min is cooled to 50 ℃ with the speed of 20 ℃/min, stops 5min; Heating rate with 20 ℃/min is warming up to the 3rd spontaneous nucleation-annealing temperature T _S3=157 ℃, stop t _s=40min, so, handle, sample is heat-treated under the spontaneous nucleation-annealing temperature that reduces successively by continuous heating and cooling, each spontaneous nucleation-annealing temperature is than low △ T=7 ℃ of a last spontaneous nucleation temperature, as sample spontaneous nucleation-annealing temperature T in the end _Sn=136 ℃ stop t down _sBehind=the 40min, be cooled to 50 ℃, stop 5min, be warming up to 210 ℃, write down final melting curve with the heating rate of 20 ℃/min;

5. the hot hierarchical test result to material carries out mathematics match and Theoretical Calculation, analyzes the stability of polypropylene material when the stretching film forming:

A. the calculating of each melting peak relative content

Use professional swarming process of fitting treatment software that final melting curve is carried out the swarming process of fitting treatment, curve is separated into melting peak independent of each other, and calculates the fusing point and the relative content at each peak, swarming the results are shown in table 3;

B. the calculating of wafer thickness distribution curve

Calculate the pairing wafer thickness of each melting peak of hot grading curve, and then the wafer thickness distribution situation of calculating acrylic resin, utilize Thomson-Gibbs equation (1) to calculate the pairing wafer thickness L of each melting peak of hot grading curve, and then calculate the wafer thickness distribution situation of acrylic resin:

$T_m={T_m}^0(1-\frac{2\mathrm{\&sigma;}}{\mathrm{\&Delta;}{H}_{0}L})---\left(1\right)$

In the formula, T _mBe polyacrylic melt temperature, polyacrylic equilibrium melting point T _m ⁰=460K, polyacrylic melting enthalpy △ H ₀=184 * 10 ⁶J/m ³, polyacrylic surface free energy σ=0.0496J/m ²

C. the calculating of wafer thickness distribution parameter

(2) formula of use and (3) formula are calculated the number average wafer thickness L of material respectively _nWith weight average wafer thickness L _w, use (4) formula to calculate the wafer thickness distribution coefficient I of material, experimental result is listed in table 4:

$L_n=\frac{n_1{\mathrm{<figure-callout\; id="1"\; label="L"\; filenames="HDA0000049116180000011.png,HDA0000049116180000012.png"\; state="\{\{state\}\}">L</figure-callout>}}_1+n_2{\mathrm{<figure-callout\; id="2"\; label="L"\; filenames="HDA0000049116180000011.png,HDA0000049116180000012.png"\; state="\{\{state\}\}">L</figure-callout>}}_2+n_3{\mathrm{<figure-callout\; id="3"\; label="L"\; filenames="HDA0000049116180000011.png,HDA0000049116180000012.png"\; state="\{\{state\}\}">L</figure-callout>}}_3+n_4{\mathrm{<figure-callout\; id="4"\; label="L"\; filenames="HDA0000049116180000011.png,HDA0000049116180000012.png"\; state="\{\{state\}\}">L</figure-callout>}}_4+,K,+n_j{\mathrm{<figure-callout\; id="1"\; label="L\; j\; n"\; filenames="HDA0000049116180000011.png,HDA0000049116180000012.png"\; state="\{\{state\}\}">L</figure-callout>}}_j}{n_{}}=\mathrm{\&Sigma;}{f}_i{L}_i---\left(2\right)$

$L_w=\frac{n_1{{\mathrm{<figure-callout\; id="1"\; label="L"\; filenames="HDA0000049116180000011.png,HDA0000049116180000012.png"\; state="\{\{state\}\}">L</figure-callout>}}_1}^2+n_2{{\mathrm{<figure-callout\; id="2"\; label="L"\; filenames="HDA0000049116180000011.png,HDA0000049116180000012.png"\; state="\{\{state\}\}">L</figure-callout>}}_2}^2+n_3{{\mathrm{<figure-callout\; id="3"\; label="L"\; filenames="HDA0000049116180000011.png,HDA0000049116180000012.png"\; state="\{\{state\}\}">L</figure-callout>}}_3}^2+n_4{{\mathrm{<figure-callout\; id="4"\; label="L"\; filenames="HDA0000049116180000011.png,HDA0000049116180000012.png"\; state="\{\{state\}\}">L</figure-callout>}}_4}^2+,K,+n_j{L_j}^2}{n_1{\mathrm{<figure-callout\; id="1"\; label="L"\; filenames="HDA0000049116180000011.png,HDA0000049116180000012.png"\; state="\{\{state\}\}">L</figure-callout>}}_1+n_2{\mathrm{<figure-callout\; id="2"\; label="L"\; filenames="HDA0000049116180000011.png,HDA0000049116180000012.png"\; state="\{\{state\}\}">L</figure-callout>}}_2+n_3{\mathrm{<figure-callout\; id="3"\; label="L"\; filenames="HDA0000049116180000011.png,HDA0000049116180000012.png"\; state="\{\{state\}\}">L</figure-callout>}}_3+n_4{\mathrm{<figure-callout\; id="4"\; label="L"\; filenames="HDA0000049116180000011.png,HDA0000049116180000012.png"\; state="\{\{state\}\}">L</figure-callout>}}_4+,...,+n_j{L}_j}=\frac{\mathrm{\&Sigma;}{f}_i{L_i}^2}{\mathrm{\&Sigma;}{f}_i{L}_i}---\left(3\right)$

$I=\frac{L_w}{L_n}---\left(4\right)$

Wherein, L ₁, L ₂... L _jBe the wafer thickness of melting peak, n ₁, n ₂... n _jIt is the relative percentage composition of melting peak area;

In addition, directly using (1) formula to carry out homogenization to hot classification melting curve handles, obtain the distribution curve of the wafer thickness of each sample that can quantitative comparison, thereby the unevenness of molecular structure regularity is reflected, and then according to the one-tenth membrane stability quality of interpretation of result acrylic resin.

From the result of table 3, table 4 as can be seen, from PP-1 to PP-5, on the hot grading curve of sample, the relative content at high-temperature fusion peak reduces gradually, the content at inferior high-temperature fusion peak increases gradually, and the average wafer thickness that resin can form diminishes, and it is big that the wafer thickness profile exponent becomes; High isotacticity components contents descends gradually, and middle low grade components contents rises gradually.Above result shows that from PP-1 to PP-5, because the decline of high isotacticity component concentration, the resin wafer thickness descends, and the easier film forming that is stretched of resin in process becomes membrane stability progressively to rise, and the rupture of membranes rate reduces gradually.This result is consistent with the test result of large-scale film balance.

Embodiment 3

Detecting the one-tenth membrane stability of polypropylene in two-way stretch with heat analysis method may further comprise the steps:

1. laboratory sample: five have different molecular structures and the isotactic polypropylene that becomes membrane stability, are numbered PP-1, PP-2, PP-3, PP-4, PP-5.Five kinds of acrylic resins are tested on large-scale membrane machine, and the result shows that from PP-1 to PP-5, the rupture of membranes rate of resin reduces gradually, becomes membrane stability to become better and better.

2. sample is pressed into the thin plate of thickness homogeneous with compression molding forming machine, preparation heat is analyzed the special test sample.

3. sample is stopped 5min down 210 ℃ of temperature, then, reduce to 40 ℃, stop 3min, sample is heated to 200 ℃, record decrease temperature crystalline curve and intensification melting curve with the heating rate of 9 ℃/min with the rate of temperature fall of 9 ℃/min;

Obtain the Tc T of material from crystallization curve _c, crystallization onset temperature T _ConsetWith crystallization final temperature T _Cendset, obtain the fusing point T of material from melting curve _m, melt initiation temperature degree T _Monset, fusion final temperature T _MendsetWith relative crystallinity X _c

4. above-mentioned sample is stopped 5min down 200 ℃ of temperature, then, reduce to 40 ℃, stop 3min, be heated to first spontaneous nucleation-annealing temperature T with the heating rate of 15 ℃/min with the rate of temperature fall of 15 ℃/min _S1=167 ℃, stop t _s=20min reduces to 40 ℃ with the rate of temperature fall of 15 ℃/min, stops 3min; Continue to be heated to second spontaneous nucleation-annealing temperature T _S2=162 ℃, stop t _s=20min reduces to 40 ℃ with the rate of temperature fall of 15 ℃/min, stops 3min; Heating rate with 15 ℃/min is warming up to the 3rd spontaneous nucleation-annealing temperature T _S3=157 ℃, stop t _s=20min, so, handle, sample is heat-treated under the spontaneous nucleation-annealing temperature that reduces successively by continuous heating and cooling, each spontaneous nucleation-annealing temperature is than low △ T=5 ℃ of a last spontaneous nucleation temperature, as sample spontaneous nucleation-annealing temperature T in the end _Sn=137 ℃ stop t down _sBehind=the 20min, be cooled to 40 ℃, stop 3min, be warming up to 200 ℃, write down final melting curve with the heating rate of 15 ℃/min;

5. the hot hierarchical test result to material carries out mathematics match and Theoretical Calculation, analyzes the stability of polypropylene material when the stretching film forming:

A. the calculating of each melting peak relative content

Use professional swarming process of fitting treatment software that final melting curve is carried out the swarming process of fitting treatment, curve is separated into melting peak independent of each other, and calculates the fusing point and the relative content at each peak, swarming the results are shown in table 5;

B. the calculating of wafer thickness distribution curve

Calculate the pairing wafer thickness of each melting peak of hot grading curve, and then the wafer thickness distribution situation of calculating acrylic resin, utilize Thomson-Gibbs equation (1) to calculate the pairing wafer thickness L of each melting peak of hot grading curve, and then calculate the wafer thickness distribution situation of acrylic resin:

$T_m={T_m}^0(1-\frac{2\mathrm{\&sigma;}}{\mathrm{\&Delta;}{H}_{0}L})---\left(1\right)$

In the formula, T _mBe polyacrylic melt temperature, polyacrylic equilibrium melting point T _m ⁰=460K, polyacrylic melting enthalpy △ H ₀=184 * 10 ⁶J/m ³, polyacrylic surface free energy σ=0.0496J/m ²

C. the calculating of wafer thickness distribution parameter

(2) formula of use and (3) formula are calculated the number average wafer thickness L of material respectively _nWith weight average wafer thickness L _w, use (4) formula to calculate the wafer thickness distribution coefficient I of material, experimental result is listed in table 6:

$L_n=\frac{n_1{\mathrm{<figure-callout\; id="1"\; label="L"\; filenames="HDA0000049116180000011.png,HDA0000049116180000012.png"\; state="\{\{state\}\}">L</figure-callout>}}_1+n_2{\mathrm{<figure-callout\; id="2"\; label="L"\; filenames="HDA0000049116180000011.png,HDA0000049116180000012.png"\; state="\{\{state\}\}">L</figure-callout>}}_2+n_3{\mathrm{<figure-callout\; id="3"\; label="L"\; filenames="HDA0000049116180000011.png,HDA0000049116180000012.png"\; state="\{\{state\}\}">L</figure-callout>}}_3+n_4{\mathrm{<figure-callout\; id="4"\; label="L"\; filenames="HDA0000049116180000011.png,HDA0000049116180000012.png"\; state="\{\{state\}\}">L</figure-callout>}}_4+,K,+n_j{\mathrm{<figure-callout\; id="1"\; label="L\; j\; n"\; filenames="HDA0000049116180000011.png,HDA0000049116180000012.png"\; state="\{\{state\}\}">L</figure-callout>}}_j}{n_{}}=\mathrm{\&Sigma;}{f}_i{L}_i---\left(2\right)$

$L_w=\frac{n_1{{\mathrm{<figure-callout\; id="1"\; label="L"\; filenames="HDA0000049116180000011.png,HDA0000049116180000012.png"\; state="\{\{state\}\}">L</figure-callout>}}_1}^2+n_2{{\mathrm{<figure-callout\; id="2"\; label="L"\; filenames="HDA0000049116180000011.png,HDA0000049116180000012.png"\; state="\{\{state\}\}">L</figure-callout>}}_2}^2+n_3{{\mathrm{<figure-callout\; id="3"\; label="L"\; filenames="HDA0000049116180000011.png,HDA0000049116180000012.png"\; state="\{\{state\}\}">L</figure-callout>}}_3}^2+n_4{{\mathrm{<figure-callout\; id="4"\; label="L"\; filenames="HDA0000049116180000011.png,HDA0000049116180000012.png"\; state="\{\{state\}\}">L</figure-callout>}}_4}^2+,K,+n_j{L_j}^2}{n_1{\mathrm{<figure-callout\; id="1"\; label="L"\; filenames="HDA0000049116180000011.png,HDA0000049116180000012.png"\; state="\{\{state\}\}">L</figure-callout>}}_1+n_2{\mathrm{<figure-callout\; id="2"\; label="L"\; filenames="HDA0000049116180000011.png,HDA0000049116180000012.png"\; state="\{\{state\}\}">L</figure-callout>}}_2+n_3{\mathrm{<figure-callout\; id="3"\; label="L"\; filenames="HDA0000049116180000011.png,HDA0000049116180000012.png"\; state="\{\{state\}\}">L</figure-callout>}}_3+n_4{\mathrm{<figure-callout\; id="4"\; label="L"\; filenames="HDA0000049116180000011.png,HDA0000049116180000012.png"\; state="\{\{state\}\}">L</figure-callout>}}_4+,...,+n_j{L}_j}=\frac{\mathrm{\&Sigma;}{f}_i{L_i}^2}{\mathrm{\&Sigma;}{f}_i{L}_i}---\left(3\right)$

$I=\frac{L_w}{L_n}---\left(4\right)$

Wherein, L ₁, L ₂... L _jBe the wafer thickness of melting peak, n ₁, n ₂... n _jIt is the relative percentage composition of melting peak area;

In addition, directly using (1) formula to carry out homogenization to hot classification melting curve handles, obtain the distribution curve of the wafer thickness of each sample that can quantitative comparison, thereby the unevenness of molecular structure regularity is reflected, and then according to the one-tenth membrane stability quality of interpretation of result acrylic resin.

From the result of table 5, table 6 as can be seen, from PP-1 to PP-5, on the hot grading curve of sample, the relative content at high-temperature fusion peak reduces gradually, the content at inferior high-temperature fusion peak increases gradually, and the average wafer thickness that resin can form diminishes, and it is big that the wafer thickness profile exponent becomes; High isotacticity components contents descends gradually, and middle low grade components contents rises gradually.Above result shows that from PP-1 to PP-5, because the decline of high isotacticity component concentration, the resin wafer thickness descends, and the easier film forming that is stretched of resin in process becomes membrane stability progressively to rise, and the rupture of membranes rate reduces gradually.This result is consistent with the test result of large-scale film balance.

The melting curve swarming result of 5 isotactic polypropylene samples of table 1 under embodiment 1 hot classification procedure

The wafer thickness distribution parameter of 5 isotactic polypropylene samples of table 2 under embodiment 1 hot classification procedure

The melting curve swarming result of 5 isotactic polypropylene samples of table 3 under embodiment 2 hot classification procedure

The wafer thickness distribution parameter of 5 isotactic polypropylene samples of table 4 under embodiment 2 hot classification procedure

The melting curve swarming result of 5 isotactic polypropylene samples of table 5 under embodiment 3 hot classification procedure

The wafer thickness distribution parameter of 5 isotactic polypropylene samples of table 6 under embodiment 3 hot classification procedure

Claims (1)

1. detect the one-tenth membrane stability of polypropylene in two-way stretch with heat analysis method, it is characterized in that this method may further comprise the steps:

(1) acrylic resin is made the hot analytical test standard model of thickness homogeneous;

(2) acrylic resin is carried out heat and analyzes the heating and cooling scan process, obtain the crystallization and the melting behavior parameter of material:

Sample is stopped 2～7min down for 180～210 ℃ in temperature, to eliminate any residual thermal history, then, sample is reduced to 25～50 ℃ with the rate of temperature fall of 7～12 ℃/min, stop 1～5min, heating rate with 7～12 ℃/min is heated to 180～210 ℃ with sample, record decrease temperature crystalline curve and intensification melting curve subsequently;

Obtain the Tc T of material from the decrease temperature crystalline curve _c, crystallization onset temperature T _ConsetWith crystallization final temperature T _Cendset, obtain the fusing point T of material from the intensification melting curve _m, melt initiation temperature degree T _Monset, fusion final temperature T _MendsetWith relative crystallinity X _c

(3) heat treatment process of hot classification:

Above-mentioned sample is stopped 2～7min down for 180～210 ℃ in temperature, to eliminate any residual thermal history, then, reduce to 25～50 ℃ with the rate of temperature fall of 5～20 ℃/min, stop 1～5min, be heated to first spontaneous nucleation-annealing temperature T with the heating rate of 5～20 ℃/min _S1=164～170 ℃, stop t _s=5～40min is cooled to 25～50 ℃ with the speed of 5～20 ℃/min, stops 1～5min; Continue to be heated to second spontaneous nucleation-annealing temperature T _S2=160～163 ℃, stop t _s=5～40min is cooled to 25～50 ℃ with the speed of 5～20 ℃/min, stops 1～5min; Heating rate with 5～20 ℃/min is warming up to the 3rd spontaneous nucleation-annealing temperature T _S3=155～159 ℃, stop t _s=5～40min, so, handle, sample is heat-treated under the spontaneous nucleation-annealing temperature that reduces successively by continuous heating and cooling, each spontaneous nucleation-annealing temperature is than the low △ T=2 of a last spontaneous nucleation temperature～7 ℃, as sample spontaneous nucleation-annealing temperature T in the end _Sn=135～142 ℃ stop t down _sBehind=5～40min, be cooled to 25～50 ℃, stop 1～5min, be warming up to 180～210 ℃, write down final melting curve with the heating rate of 5～20 ℃/min;

(4) polyacrylic hot hierarchical test result is carried out mathematics match and Theoretical Calculation, analyzes the stability of polypropylene material when the stretching film forming:

A. the calculating of each melting peak relative content

Use professional swarming process of fitting treatment software that final melting curve is carried out the swarming process of fitting treatment, curve is separated into melting peak independent of each other, and calculate the fusing point and the relative content at each peak;

B. the calculating of wafer thickness distribution curve

Calculate the pairing wafer thickness of each melting peak of hot grading curve, and then the wafer thickness distribution situation of calculating acrylic resin, utilize Thomson-Gibbs equation (1) to calculate the pairing wafer thickness L of each melting peak of hot grading curve, and then calculate the wafer thickness distribution situation of acrylic resin:

$T_m={T_m}^0(1-\frac{2\mathrm{\&sigma;}}{\mathrm{\&Delta;}{H}_{0}L})---\left(1\right)$

In the formula, T _mBe polyacrylic melt temperature, T _m ⁰Be polyacrylic equilibrium melting point, △ H ₀Be polyacrylic melting enthalpy, σ is polyacrylic surface free energy;

C. the calculating of wafer thickness distribution parameter

(2) formula of use and (3) formula are calculated polyacrylic number average wafer thickness L respectively _nWith weight average wafer thickness L _w, use (4) formula to calculate the wafer thickness distribution coefficient I of material:

$L_n=\frac{n_1{L}_1+n_2{L}_2+n_3{L}_3+n_4{L}_4+,K,+n_j{L}_j}{n_1+n_2+n_3+n_4+,...,+n_j}=\mathrm{\&Sigma;}{f}_i{L}_i---\left(2\right)$

$L_w=\frac{n_1{L_1}^2+n_2{L_2}^2+n_3{L_3}^2+n_4{L_4}^2+,K,+n_j{L_j}^2}{n_1{L}_1+n_2{L}_2+n_3{L}_3+n_4{L}_4+,...,+n_j{L}_j}=\frac{\mathrm{\&Sigma;}{f}_i{L_i}^2}{\mathrm{\&Sigma;}{f}_i{L}_i}---\left(3\right)$

$I=\frac{L_w}{L_n}---\left(4\right)$

Wherein, L ₁, L ₂... L _jBe the wafer thickness of melting peak, n ₁, n ₂... n _jIt is the relative percentage composition of melting peak area;

In addition, directly using (1) formula to carry out homogenization to hot classification melting curve handles, obtain the distribution curve of the wafer thickness of each sample that can quantitative comparison, thereby the unevenness of molecular structure regularity is reflected, and then according to the one-tenth membrane stability quality of interpretation of result acrylic resin.

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