阅读说明：本技术 一种bopp薄膜增刚剂的制备方法 (Preparation method of BOPP film stiffening agent ) 是由 杨孟君 王斌 孙向东 于 2021-09-17 设计创作，主要内容包括：本发明涉及一种BOPP薄膜增刚剂的制备方法,包括：将环戊二烯或其衍生物与降冰片烯类单体或C8环烯烃作为共聚原料,先经连续高温聚合获得聚合树脂液,再通过两段催化加氢反应,并脱除低沸点轻组分和溶剂,制备得到高软化点脂肪族加氢石油树脂；再与均聚聚丙烯混合挤出获得BOPP薄膜增刚剂。本发明制备的增刚剂具有非常好的抗溶出性能和环保性能,适用于BOPP烟膜改性,具有良好的市场应用前景。(The invention relates to a preparation method of a BOPP film stiffening agent, which comprises the following steps: taking cyclopentadiene or derivatives thereof and norbornene monomers or C8 cycloolefins as copolymerization raw materials, firstly carrying out continuous high-temperature polymerization to obtain a polymer resin liquid, then carrying out two-stage catalytic hydrogenation reaction, and removing low-boiling-point light components and solvents to prepare the high-softening-point aliphatic hydrogenated petroleum resin; then mixing the BOPP film stiffening agent with the homopolymerized polypropylene and extruding the mixture to obtain the BOPP film stiffening agent. The stiffening agent prepared by the invention has very good anti-dissolution performance and environmental protection performance, is suitable for modifying a BOPP smoke film, and has good market application prospect.)

1. A preparation method of a BOPP film stiffening agent comprises the following steps:

(1) uniformly mixing cyclopentadiene or derivatives thereof with norbornene monomers or C8 cycloolefins according to the mass ratio of 1 (0.1-0.5) to obtain a polymerization raw material, and then adding polyether polyol accounting for 0.05-5.0% of the total mass of the materials; firstly, adding a reaction solvent accounting for 30-60% of the total material mass into a high-pressure reaction kettle (R101) with a stirrer, carrying out polymerization reaction for 10-20 h at 220-250 ℃, and then carrying out polymerization reaction for 10-20 h at 240-270 ℃ in a high-pressure reaction kettle (R102) with a stirrer to obtain a polymerization solution;

(2) removing unreacted raw materials from the polymerization solution obtained in the step (1) in a flash tank (V101) at the pressure of 0.07-0.08 MPa and the temperature of 70-75 ℃, mixing the polymerization solution with a supplementary solvent after passing through an adsorption packed tower (T201), conveying the mixture to a loop hydrogenation reactor (R201), and reacting with H under the action of a powder-loaded nickel catalyst at the temperature of 140-180 DEG C₂Reacting at a liquid hourly space velocity of 0.3-0.5 h^-1To obtain a mixture of the hydrogenated resin liquid A and the catalyst;

(3) the mixture obtained in the step (2) passes through a filter (F201), powder-loaded nickel catalyst is separated out from the bottom, and the top material is conveyed to a packed tower (T202) for adsorption and desorptionAfter removing impurities, the mixture enters a hydrogenation reactor (R202) and is subjected to Ni-Mo/gamma-Al₂O₃Reacting with H at 190-240 ℃ under the action of a catalyst₂Reacting at a liquid hourly space velocity of 2-5 h^-1Obtaining hydrogenated resin liquid B; mixing the removed powder loaded nickel catalyst with a supplementary solvent, heating the mixture to 130-160 ℃ by a heat exchanger (E201), and returning the mixture to a loop hydrogenation reactor (R201);

(4) the hydrogenated resin liquid B obtained in the step (3) is conveyed to a flash evaporator (V301), the solvent is removed at the vacuum degree of-0.085 to-0.095 MPa and the temperature of 200 to 250 ℃, the hydrogenated resin liquid C obtained at the bottom is conveyed to a rectifying tower (T301), the low-boiling-point light component and the residual solvent are removed by rectification at the vacuum degree of-0.085 to-0.095 MPa and the temperature of 200 to 250 ℃, and the aliphatic hydrogenated petroleum resin with high softening point is obtained at the bottom of the tower;

(5) and (4) extruding the high-softening-point aliphatic hydrogenated petroleum resin obtained in the step (4) and the homo-polypropylene by a double-screw extruder according to the mass ratio of 1:1, adding an antioxidant, granulating and cooling to obtain the BOPP film stiffening agent.

2. The method of claim 1, wherein: the cyclopentadiene or the derivative thereof in the step (1) is one or a mixture of cyclopentadiene, methyl cyclopentadiene, ethyl cyclopentadiene, dicyclopentadiene and methyl cyclopentadiene dimer.

3. The method of claim 1, wherein: the norbornene monomer in the step (1) is one or a mixture of 2, 5-norbornadiene and 5-ethylidene-2-norbornene; the C8 cycloolefine is one or the mixture of 5-vinyl-2-cyclohexene and 1, 3-cyclohexadiene.

4. The method of claim 1, wherein: the polyether polyol in the step (1) is propylene glycol polyether PPG or polytetrahydrofuran glycol PTHF.

5. The method of claim 1, wherein: the reaction solvent in the step (1) is one or more of cyclohexane, methylcyclohexane, cyclopentane and hydrogenated naphthenic oil.

6. The method of claim 1, wherein: the supplementary solvent in the steps (2) and (3) is heavily hydrogenated naphthenic oil.

7. The method of claim 1, wherein: the Ni content of the powder-loaded nickel catalyst in the step (2) is 60-70%, the carrier is silicon dioxide, the average particle size is 15-50 mu m, and the specific surface area is 150-220 m²/g。

8. The method of claim 1, wherein: Ni-Mo/gamma-Al in the step (3)₂O₃The catalyst is prepared by an immersion method, wherein the Ni load content is 15-35%, the Mo load content is 1-3%, and the size is phi 5 x (4-6) mm.

9. The method of claim 1, wherein: the set temperature of the double-screw extruder in the step (5) is 250-260 ℃, and the melt temperature is 235-245 ℃.

10. The method of claim 1, wherein: the antioxidant in the step (5) is antioxidant BHT, and the adding amount is 0.3-0.4% of the total material mass.

Technical Field

The invention belongs to the field of film materials, and particularly relates to a preparation method of a BOPP film stiffening agent.

Background

The BOPP cigarette film is also called a biaxially oriented polypropylene cigarette film, which is called a cigarette film for short, and is formed by co-extruding and stretching a plurality of polypropylene functional materials. At present, domestic manufacturers generally adopt a three-layer (A/B/C) coextrusion technology to prepare a high-performance BOPP cigarette film through biaxial stretching, and the film is colorless, odorless, tasteless and nontoxic, has a certain barrier function to smell and moisture, and has high tensile strength, impact strength, rigidity, toughness, luster and good transparency, so that the film is an ideal material for cigarette packaging.

In the extrusion process of the middle layer of the BOPP smoke film, 10-20% of a stiffening agent is usually required to be added to improve the elastic modulus of the film, improve the heat shrinkage, transparency, glossiness and the like, simultaneously reduce the processing temperature and improve the extending and film-forming properties of PP, and the stiffening agent is usually a finish-processed mixture taking hydrogenated C5 or C9 petroleum resin as a main material. In patent CN103087401A, the weight part of petroleum resin in the polypropylene resin composition for preparing the packaging film is 10-30 parts, which is required to be C5 or C9 fraction in the byproduct obtained by petroleum cracking, or a mixture thereof, and is preferably cyclopentadiene type petroleum resin or petroleum resin with cyclopentadiene type as the main component. In patent CN108715070A, the effective component of a stiffening agent master batch selected for a core layer of an anti-wrinkle and anti-cigarette packet deformation BOPP film is C9 hydrogenated resin with a high Vickers softening point of 180-185 ℃, so that the stiffness of the film and the contractibility required by packaging are ensured, but the instant shrinkage rate is not easy to control, the fluctuation is large, and the packaging contractibility is large. In patent CN106313838A, in the preparation method of the high-transparency cigarette film, the dried raw materials of the lower surface layer, the intermediate core layer, and the upper surface layer are respectively sent to respective extruders for melt-mixing, wherein the intermediate core layer comprises the following components by mass: 85-90% of homo-polypropylene and 10-15% of a stiffening agent.

As is known from the above patent, the stiffening agent used in the BOPP smoke film core layer is usually a petroleum resin made from a C5 fraction or a C9 fraction, and is usually a cyclopentadiene type resin having a high softening point, good environmental friendliness, and similar polarity to PP. However, the above patent only aims at the injection molding technology of the BOPP film stiffening agent, and basically does not introduce the preparation process of the resin.

Patent CN111971314A discloses the high temperature polymerization of at least one cyclic diene component and at least one ethylenically unsaturated aromatic component and the preparation of hydrocarbon resins by hydrogenation over a nickel catalyst. The invention mainly uses aromatic components as comonomers to lead petroleum resin to be introduced into a six-membered ring structure, thereby improving the modification effect of the petroleum resin in products such as paint, plastic, rubber and the like.

Disclosure of Invention

The invention aims to solve the technical problem of providing a preparation method of a BOPP film stiffening agent, and the prepared stiffening agent has very good dissolution resistance and environmental protection performance, is suitable for modifying a BOPP cigarette film and has good market application prospect.

The invention provides a preparation method of a BOPP film stiffening agent, which comprises the following steps:

(1) uniformly mixing cyclopentadiene or derivatives thereof with norbornene monomers or C8 cycloolefins according to the mass ratio of 1 (0.1-0.5) to obtain a polymerization raw material, and then adding polyether polyol accounting for 0.05-5.0% of the total mass of the materials; firstly, adding a reaction solvent accounting for 30-60% of the total material mass into a high-pressure reaction kettle (R101) with a stirrer, carrying out polymerization reaction for 10-20 h at 220-250 ℃, and then carrying out polymerization reaction for 10-20 h at 240-270 ℃ in a high-pressure reaction kettle (R102) with a stirrer to obtain a polymerization solution;

(2) removing unreacted raw materials from the polymerization liquid obtained in the step (1) in a flash tank at the pressure of 0.07-0.08 MPa and the temperature of 70-75 ℃, mixing the polymerization liquid with a supplementary solvent after passing through an adsorption packing tower, conveying the mixture to a loop hydrogenation reactor, and reacting the mixture with H under the action of a powder-loaded nickel catalyst at the temperature of 140-180 DEG C₂Reacting at a liquid hourly space velocity of 0.3-0.5 h^-1To obtain a mixture of the hydrogenated resin liquid A and the catalyst;

(3) the mixture obtained in the step (2) passes through a filter, powder-loaded nickel catalyst is separated out from the bottom of the mixture, the top material is conveyed to a packed tower, and enters a hydrogenation reactor after impurities are removed by adsorption, and the mixture is subjected to Ni-Mo/gamma-Al₂O₃Reacting with H at 190-240 ℃ under the action of a catalyst₂Reacting at a liquid hourly space velocity of 2-5 h^-1Obtaining hydrogenated resin liquid B; mixing the removed powder loaded nickel catalyst with a supplementary solvent, heating the mixture to 130-160 ℃ by a heat exchanger, and returning the mixture to the loop hydrogenation reactor;

(4) conveying the hydrogenated resin liquid B obtained in the step (3) to a flash evaporator, removing the solvent at the vacuum degree of-0.085 to-0.095 MPa and the temperature of 200 to 250 ℃, conveying the hydrogenated resin liquid C obtained at the bottom to a rectifying tower, rectifying and removing low-boiling-point light components and residual solvent at the vacuum degree of-0.085 to-0.095 MPa and the temperature of 200 to 250 ℃, and obtaining the high-softening-point aliphatic hydrogenated petroleum resin at the tower bottom;

(5) and (4) extruding the high-softening-point aliphatic hydrogenated petroleum resin obtained in the step (4) and the homo-polypropylene by a double-screw extruder according to the mass ratio of 1:1, adding an antioxidant, granulating and cooling to obtain the BOPP film stiffening agent.

The cyclopentadiene or the derivative thereof in the step (1) is one or a mixture of cyclopentadiene, methyl cyclopentadiene, ethyl cyclopentadiene, dicyclopentadiene and methyl cyclopentadiene dimer.

The norbornene monomer in the step (1) is one or a mixture of 2, 5-norbornadiene and 5-ethylidene-2-norbornene; the C8 cycloolefine is one or the mixture of 5-vinyl-2-cyclohexene and 1, 3-cyclohexadiene.

The polyether polyol in the step (1) is propylene glycol polyether PPG or polytetrahydrofuran glycol PTHF.

The reaction solvent in the step (1) is one or more of cyclohexane, methylcyclohexane, cyclopentane and hydrogenated naphthenic oil.

The supplementary solvent in the steps (2) and (3) is heavily hydrogenated naphthenic oil. The heavily hydrogenated naphthenic base oil has a density of 0.91-0.93 g/cm³The kinematic viscosity is 20-85 cSt, and the aniline point is 72-80 ℃.

The specification of the filler of the adsorption filler tower in the step (2) is that the upper layer is alpha-alumina, the lower layer is foamed ceramic, and the average diameter of the filler is 13-25 mm.

The powder in the step (2)The Ni content of the nickel-supported catalyst is 60-70%, the carrier is silicon dioxide, the average particle size is 15-50 mu m, and the specific surface area is 150-220 m²/g。

Ni-Mo/gamma-Al in the step (3)₂O₃The catalyst is prepared by an immersion method, wherein the Ni load content is 15-35%, the Mo load content is 1-3%, and the size is phi 5 x (4-6) mm.

And (4) adopting foamed ceramic as the filler of the packed tower in the step (3), wherein the average diameter of the filler is 13-25 mm.

The softening point of the high-softening-point aliphatic hydrogenated petroleum resin obtained in the step (4) is 120-160 ℃, the Gardner color number is less than or equal to 1#, the Z-average molecular weight Mz is 750-2300, and the Mw/Mn is less than or equal to 1.8.

The homo-polypropylene in the step (5) is in a film grade, the melt flow rate (MI) is 4-10 g/10min, the shrinkage rate is 1.5-2.0%, and the Rockwell hardness is 76-78.

The set temperature of the double-screw extruder in the step (5) is 250-260 ℃, and the melt temperature is 235-245 ℃.

The antioxidant in the step (5) is antioxidant BHT, and the adding amount is 0.3-0.4% of the total material mass.

The tensile elastic modulus of the BOPP stiffening agent obtained in the step (5) is 1000-2500 Mpa, and the content of Volatile Organic Compounds (VOC) is less than or equal to 2 g/L.

Advantageous effects

(1) The invention uses norbornene monomer, C8 cycloolefine and other non-aromatic cyclic monomer to copolymerize with cyclopentadiene CPD or its derivative, can adjust the polymer activity, improve the polymerization degree of cyclopentadiene and its derivative, and adopts two-stage hydrogenation process to obtain alicyclic petroleum resin with high softening point and narrow molecular weight distribution, which has higher softening point and molecular rigidity and can be used for BOPP stiffening modification;

(2) according to the invention, a small amount of polyether polyol is adopted as a reaction raw material to adjust the polarity of the liquid material, so that a gel compound is prevented from being generated, and the self-polymerization of methyl cyclopentadiene is reduced;

(3) the invention uses different nickel catalysts and adopts two-stage hydrogenation catalytic process to obtain the fully hydrogenated petroleum resin, which has excellent light-heat resistant stability and environmental protection performance;

(4) the first-stage hydrogenation adopts a loop hydrogenation reactor process, so that the resin hydrogenation efficiency is enhanced, the product conversion rate is improved, and the catalyst cost is reduced;

(5) the two-stage hydrogenation catalyst adopts Ni-Mo/gamma-Al₂O₃The fixed bed catalyst has better hydrogenation selectivity and is suitable for deep hydrogenation of the alicyclic resin;

(6) according to the invention, a large amount of oligomers are removed through a reduced pressure flash evaporation-rectification process, and the BOPP smoke film stiffening agent with low dissolution and low Volatile Organic Compounds (VOC) can be obtained after blending hydrogenated petroleum resin and homo-polypropylene.

Drawings

FIG. 1 is a schematic process flow diagram of the present invention.

Detailed Description

The invention will be further illustrated with reference to the following specific examples. It should be understood that these examples are for illustrative purposes only and are not intended to limit the scope of the present invention. Further, it should be understood that various changes or modifications of the present invention may be made by those skilled in the art after reading the teaching of the present invention, and such equivalents may fall within the scope of the present invention as defined in the appended claims.

Stiffness is a key performance for measuring the quality of the BOPP cigarette film, and a film formed by injection molding and stretching of PP alone is generally softer and cannot meet the use requirement of the cigarette film. Therefore, the rigidity-increasing modifier is added into the core layer when the smoke film is injected. The stiffness characterization of the BOPP tobacco film adopts "determination of tensile properties of plastics part 3: test conditions for thin plastics and sheets GB/T1040.3-2006, judged by testing the tensile modulus of elasticity (E, stiffness index).

The dissolution resistance index of the BOPP cigarette film is mainly judged by measuring the content of Volatile Organic Compounds (VOC) of the material at high temperature, and is measured by a method specified in the standard GB/T23986-one 2009.

Example 1

(1) Uniformly mixing CPD and NBDE according to the mass ratio of 1: 0.2 to obtain a polymerization raw material, adding PPG (photoplethysmography) accounting for 0.5% of the total mass of the materials, adding methylcyclohexane accounting for 50% of the total mass of the materials into a high-pressure reaction kettle R101 with stirring, carrying out polymerization reaction for 12 hours at 235 ℃, and carrying out polymerization reaction for 12 hours at 240 ℃ in a high-pressure reaction kettle R102 with stirring to obtain a polymerization solution.

(2) Removing unreacted raw materials from the polymerization solution in a flash tank V101 at the pressure of 0.075MPa and the temperature of 73 ℃, mixing the polymerization solution with a supplemented heavily hydrogenated naphthenic oil solvent after passing through an adsorption packed tower T201, conveying the mixture to a loop hydrogenation reactor R201, and reacting the mixture with H at the temperature of 160 ℃ under the action of a powder supported nickel catalyst₂Reaction at liquid hourly space velocity of 0.33h^-1And obtaining a hydrogenated resin liquid A and a catalyst mixture.

(3) The mixture passes through a filter F201, powder-loaded nickel catalyst is separated out from the bottom, the top material is conveyed to a packed tower T202, impurities such as catalyst powder and the like are adsorbed and removed, and then the mixture enters a hydrogenation reactor R202 and is subjected to Ni-Mo/gamma-Al reaction₂O₃Reacting with H at 220 ℃ under the action of a catalyst₂Reaction at liquid hourly space velocity of 2h^-1To obtain hydrogenated resin liquid B. The powder loaded nickel catalyst removed by the filter F201 is mixed with a supplemented heavily hydrogenated naphthenic oil solvent, heated to 160 ℃ by a heat exchanger E201 and then returned to R201.

(4) And (3) conveying the hydrogenated resin liquid B to a flash evaporator V301, removing the solvent by flash evaporation at the vacuum degree of-0.085 MPa and the temperature of 215 ℃, conveying the hydrogenated resin liquid C obtained at the bottom to a rectifying tower T301, rectifying and removing low-boiling-point light components and residual solvent at the vacuum degree of-0.085 MPa and the temperature of 245 ℃, and obtaining the high-softening-point aliphatic hydrogenated petroleum resin with the softening point of 136 ℃, the Gardner color number of 0.3#, the Mz of 1250 and the Mw/Mn of 1.45 at the tower bottom.

(5) The obtained high-softening-point aliphatic hydrogenated petroleum resin and the homopolymerized polypropylene are extruded by a double-screw extruder according to the mass ratio of 1:1, antioxidant BHT with the total material mass of about 0.3% is added at the same time, and the BOPP stiffening agent with the tensile elastic modulus of 1750MPa and the Volatile Organic Compound (VOC) of 0.5g/L is obtained after granulation and cooling.

Examples 2 to 6

In the embodiments 2 to 6, only the mutual proportion of CPD, NBDE and PPG is adjusted, and the other adopted process conditions are the same as those in the embodiment 1, namely, the influence of different ingredients on the performance of the hydrogenated petroleum resin is obtained.

From the above examples, it can be seen that as the proportion of NBDE in the polymerization batch increases, both the softening point and the Z-average molecular weight (Mz) of the hydrogenated petroleum resin tend to decrease; while the content of the regulator PPG is increased, which contributes to the reduction of Mz and molecular weight distribution Mw/Mn. As the raw materials of the ingredients are purified, the correlation between the color number of the hydrogenated petroleum resin and the ingredients is low.

Example 7

(1) Uniformly mixing MCPD and NBDE according to the mass ratio of 1: 0.3 to obtain a polymerization raw material, adding PTHF accounting for 1.5% of the total material mass, adding methylcyclohexane accounting for 50% of the total material mass into a high-pressure reaction kettle R101 with stirring, carrying out polymerization reaction for 10 hours at 235 ℃, and carrying out polymerization reaction for 10 hours at 250 ℃ in a high-pressure reaction kettle R102 with stirring to obtain a polymerization solution.

(2) Removing unreacted raw materials from the polymerization solution in a flash tank V101 at the pressure of 0.075MPa and the temperature of 73 ℃, mixing the polymerization solution with a supplemented heavily hydrogenated naphthenic oil solvent after passing through an adsorption packed tower T201, conveying the mixture to a loop hydrogenation reactor R201, and reacting the mixture with H under the action of a powder-loaded nickel catalyst at the temperature of 140 DEG C₂Reaction at liquid hourly space velocity of 0.5h^-1And obtaining a hydrogenated resin liquid A and a catalyst mixture.

(3) The mixture passes through a filter F201, a supported nickel catalyst is separated from the bottom, the top material is conveyed to a packed tower T202, impurities such as catalyst powder and the like are adsorbed and removed, and then the mixture enters a hydrogenation reactor R202 and is subjected to Ni-Mo/gamma-Al₂O₃With H at 200 ℃ under the action of a catalyst₂Reaction at liquid hourly space velocity of 5h^-1To obtain hydrogenated resin liquid B. The loaded nickel catalyst removed by the filter is mixed with a supplemented heavily hydrogenated naphthenic oil solvent and passes through a heat exchangerE201 was heated to 160 ℃ and returned to R201.

(4) And (3) conveying the hydrogenated resin liquid B to a flash evaporator V301, removing the solvent by flash evaporation at the vacuum degree of-0.085 MPa and the temperature of 230 ℃, conveying the hydrogenated resin liquid C obtained at the bottom to a rectifying tower T301, rectifying and removing low-boiling-point light components and residual solvent at the vacuum degree of-0.085 MPa and the temperature of 245 ℃, and obtaining the aliphatic hydrogenated petroleum resin with the softening point of 134 ℃, the Gardner color number of 0.9#, the Mz of 1460 and the Mw/Mn of 1.55 at the tower bottom.

Examples 8 to 11

Examples 8 to 11 are the aliphatic hydrogenated petroleum resins with different properties obtained by adjusting the two-stage hydrogenation process conditions by using the blending and polymerization reaction conditions of example 7.

From the above examples, it is understood that as the problem of hydrogenation reaction increases and the liquid hourly space velocity decreases, the hydrogenation degree of the aliphatic hydrogenated petroleum resin increases, the softening point and the color number decrease significantly, but the Z-average molecular weight and the molecular weight distribution index of the resin do not change significantly.

Example 12

(1) Uniformly mixing CPD, MCPD, VCH and 1,3-CHD according to the mass ratio of 1: 0.15 to serve as polymerization raw materials, then adding PTHF accounting for 1.5% of the mass of the total materials, firstly adding methylcyclohexane accounting for 50% of the mass of the total materials into a high-pressure reaction kettle R101 with stirring, carrying out polymerization reaction for 10 hours at 235 ℃, and then carrying out polymerization reaction for 12 hours at 247 ℃ in a high-pressure reaction kettle R102 with stirring to obtain a polymerization solution.

(2) Removing unreacted raw materials from the polymerization solution in a flash tank V101 at the pressure of 0.075MPa and the temperature of 73 ℃, mixing the polymerization solution with a supplemented heavily hydrogenated naphthenic oil solvent after passing through an adsorption packed tower T201, conveying the mixture to a loop hydrogenation reactor R201, and loading a nickel catalyst on powderUnder the action of hydrogen at 140 DEG C₂Reaction at liquid hourly space velocity of 0.5h^-1And obtaining a hydrogenated resin liquid A and a catalyst mixture.

(3) The mixture passes through a filter F201, a supported nickel catalyst is separated from the bottom, the top material is conveyed to a packed tower T202, impurities such as catalyst powder and the like are adsorbed and removed, and then the mixture enters a hydrogenation reactor R202 and is subjected to Ni-Mo/gamma-Al₂O₃With H at 200 ℃ under the action of a catalyst₂Reaction at liquid hourly space velocity of 5h^-1To obtain hydrogenated resin liquid B. The supported nickel catalyst removed by the filter is mixed with a supplemented heavily hydrogenated naphthenic oil solvent, heated to 160 ℃ by a heat exchanger E201 and then returned to R201.

(4) And (3) conveying the hydrogenated resin liquid B to a flash evaporator V301, removing the solvent by flash evaporation at the vacuum degree of-0.085 MPa and the temperature of 230 ℃, conveying the hydrogenated resin liquid C obtained at the bottom to a rectifying tower T301, rectifying at the vacuum degree of-0.085 MPa and the temperature of 245 ℃ to remove low-boiling-point light components and residual solvent, and obtaining the aliphatic hydrogenated petroleum resin with the softening point of 142 ℃, the Gardner color number of 0.3#, the Mz of 1670 and the Mw/Mn of 1.61 at the tower bottom.

Example 13

The hydrogenated petroleum resins obtained in example 7 and example 11 were used as raw materials, respectively, and were extruded from a twin-screw extruder (extrusion temperature 260 ℃, melt temperature 240 ℃) in a mass ratio of 1:1 with homopolypropylene (MI: 6g/10min, shrinkage 1.6%, rockwell hardness 76), and BHT, an antioxidant in an amount of about 0.3% by mass of the total material, was added, and the properties of BOPP reinforcements obtained by granulation and cooling were compared as follows:

performance of stiffening agent	Ⅰ	Ⅱ
			Tensile modulus of elasticity, MPa	1930	2180
Volatile Organic Compounds (VOC), g/L	0.4	0.7

Note: the stiffening agents I and II were respectively samples of examples 7 and 11 extruded with homopolymeric PP.

From the above examples, it can be seen that the hydrogenated resin with higher softening point and Mz molecular weight and the stiffening agent for PP extrusion molding have smaller tensile elastic modulus, and the modified BOPP film has smaller rigidity and better flexibility, and is easier to stretch and mold.