PEVA waterproof vapor-proof film and preparation method thereof

Abstract

The invention provides a PEVA waterproof vapor-proof film and a preparation method thereof, and the PEVA waterproof vapor-proof film comprises the following components by weight: 62-78 parts of a polyethylene-vinyl acetate copolymer, 5-12 parts of a flexibilizer, 5-10 parts of a waterproof vapor-proof auxiliary agent, 1-3 parts of an antioxidant, 0.5-2 parts of a light stabilizer, and 1-2 parts of a lubricant. According to the invention, the content of each component is regulated and controlled, so that the mechanical properties and waterproof and vapor-proof properties of the PEVA waterproof and vapor-proof film are effectively enhanced, the toughening without rigidity reduction is realized, and the weather resistance of the waterproof and vapor-proof film is improved; finally, all the components are uniformly dispersed in combination with a gradient temperature control calendering process, an efficient waterproof vapor-proof structure is formed, and experiments prove that the water vapor permeability of the PEVA waterproof vapor-proof film is smaller than 1.5 g / m < 2 >. 24h, the hydrostatic pressure resistance is larger than 150kPa, the tensile strength reaches 12-18MPa, the elongation at break is not lower than 500%, the thickness deviation of the 0.05-0.2 mm film is controlled to be smaller than + / -5%, and the waterproof vapor-proof film has the good waterproof vapor-proof performance. And the stability in the machining process and the consistency of the product quality are also improved while good mechanical properties are guaranteed.

Description

Technical Field

[0001] The invention relates to the technical field of waterproof vapor barrier films, and in particular to a PEVA waterproof vapor barrier film and a preparation method thereof. Background Art

[0002] The waterproof and vapor barrier performance of the building envelope system directly affects the durability of the structure and energy-saving efficiency. Traditional PE films and non-woven fabrics have defects such as weak puncture resistance, easy damage during construction, and poor overlap sealing, which lead to water vapor penetration, insulation failure and mold growth. PEVA (polyethylene-vinyl acetate copolymer) is a polar polymer that combines the chemical resistance of PE and the flexibility of EVA, but its pure film has problems such as low strength, poor heat resistance, and easy thermal oxidation degradation.

[0003] In the related art, the flexibility of PEVA film is generally improved by adding plasticizers or nanofillers to polyethylene-vinyl acetate copolymer. However, this method will greatly sacrifice the strength of the PEVA film, and the introduction of nanofillers will also lead to the deterioration of the mechanical properties of the PEVA film. In addition, the calendering process is prone to melt fracture and thickness deviation, which seriously affects the mechanical properties and waterproof and vapor barrier properties of the PEVA film.

[0004] Based on this, there is an urgent need to provide a PEVA waterproof vapor barrier film and a preparation method thereof. Summary of the invention

[0005] The embodiment of the present invention provides a PEVA waterproof vapor barrier film and a preparation method thereof, which can solve the problem that the traditional PEVA film cannot have both good mechanical properties and waterproof vapor barrier properties.

[0006] In the first aspect, the present invention provides a PEVA waterproof vapor barrier film, which comprises the following components in parts by weight: polyethylene-vinyl acetate copolymer: 62-78 parts, toughening agent: 5-12 parts, waterproof vapor barrier auxiliary agent: 5-10 parts, antioxidant: 1-3 parts, light stabilizer: 0.5-2 parts, and lubricant: 1-2 parts.

[0007] Preferably, the mass content of vinyl acetate in the polyethylene-vinyl acetate copolymer is 22-28%.

[0008] Preferably, the toughening agent is at least one of styrene-butadiene-styrene block copolymer, thermoplastic polyurethane elastomer or polyolefin elastomer;

[0009] The waterproof and vapor-isolating auxiliary agent is at least one of an organic silicon waterproofing agent, nano-montmorillonite or mica powder;

[0010] The antioxidant is one of hindered phenol antioxidant KY-1076, phosphite antioxidant 168, dilauryl thiodipropionate or compound antioxidant Finox B215;

[0011] The light stabilizer is at least one of 2-hydroxy-4'-methoxydibenzophenone, hindered amine light stabilizer HS-944 or phenyl salicylate;

[0012] The lubricant is at least one of microcrystalline wax, calcium stearate and pentaerythritol stearate.

[0013] Preferably, the mass ratio of the waterproof and vapor-barrier aid to the lubricant is (5-10):(1-2).

[0014] More preferably, the mass ratio of the antioxidant to the light stabilizer is (1-3):(0.5-2).

[0015] Preferably, by weight, it includes the following components: ethylene-vinyl acetate copolymer: 65-75 parts, toughening agent: 8-12 parts, waterproof and vapor-barrier aid: 6-10 parts, antioxidant: 1-3 parts, light stabilizer: 0.5-2 parts, lubricant: 1-2 parts.

[0016] In a second aspect, the present invention also provides a preparation method of the PEVA waterproof and vapor-barrier film described in any one of the above first aspects, and the preparation method includes the following steps:

[0017] (1) Mix the ethylene-vinyl acetate copolymer, toughening agent, waterproof and vapor-barrier aid, antioxidant, light stabilizer and lubricant in proportion to obtain a mixed material;

[0018] (2) Add the mixed material into a twin-screw extruder for extrusion granulation to obtain a mixed material masterbatch; wherein, the twin-screw extruder includes several zones, and along the direction from the feed port to the discharge port, the temperature gradient of each zone rises;

[0019] (3) Add the mixed material masterbatch into a calender for calendering to obtain the PEVA waterproof and vapor-barrier film; wherein, the calender includes several working rolls, and along the direction from the feed roll to the discharge roll, the temperature gradient of each working roll drops and the rotational speed gradient rises.

[0020] Preferably, before step (1), it further includes: the step of drying the ethylene-vinyl acetate copolymer and the waterproof and vapor-barrier aid respectively.

[0021] More preferably, the drying temperature of the ethylene-vinyl acetate copolymer is 80-90°C and the time is 2-3h.

[0022] More preferably, the drying temperature of the waterproof and vapor-barrier additive is 100-120°C, and the time is 1-2h.

[0023] Preferably, in step (1), the temperature for mixing is 70-80°C, and the time is 15-20min.

[0024] Preferably, in step (2), the twin-screw extruder includes 5 zones; among them, the temperature of the first zone of the twin-screw extruder is 130-140°C, the temperature of the second zone is 140-150°C, the temperature of the third zone is 150-160°C, the temperature of the fourth zone is 160-170°C, the temperature of the head is 170-180°C, and the rotational speed of the twin-screw is 180-220r / min.

[0025] Preferably, in step (3), the calender includes a feeding roller, a first intermediate roller, a second intermediate roller, a final roller, and a cooling roller arranged in sequence; among them, the temperature of the feeding roller is 110-130°C, and the rotational speed is 8-10rpm; the temperature of the first intermediate roller is 110-120°C, and the rotational speed is 10-12rpm; the temperature of the second intermediate roller is 100-110°C, and the rotational speed is 12-15rpm; the temperature of the final roller is 90-100°C, and the rotational speed is 18-25rpm; the temperature of the cooling roller is 40-60°C, and the rotational speed is 25-28rpm.

[0026] The present invention has at least the following beneficial effects compared with the prior art:

[0027] (1) In the present invention, first, by regulating the content of vinyl acetate in the polyethylene-vinyl acetate copolymer, the properties and compatibility of the polyethylene-vinyl acetate copolymer are regulated. Then, a toughening agent, a waterproof and vapor-barrier additive, an antioxidant, a light stabilizer, and a lubricant are further added, and the content of each component is regulated. Thus, not only the mechanical properties and waterproof and vapor-barrier properties of the PEVA waterproof and vapor-barrier film are effectively enhanced, achieving "toughening without reducing rigidity", but also the weather resistance of the waterproof and vapor-barrier film is improved; finally, combined with the gradient temperature control calendering process, each component is uniformly dispersed to form an efficient waterproof and vapor-barrier structure. After experimental verification, the water vapor transmission rate of the PEVA waterproof and vapor-barrier film in the present invention is less than 1.5g / m 2 ·24h, and the hydrostatic pressure resistance is greater than 150kPa, which can effectively prevent the penetration of water vapor, avoid the failure of the insulation layer due to moisture, and provide a reliable waterproof and vapor-barrier guarantee for the building envelope system;

[0028] (2) In the present invention, during the preparation of the PEVA waterproof and vapor-barrier film, a calendering method combining gradient rotational speed and temperature difference is adopted in the process, which improves the plasticization uniformity of the melt formed by the mixing of each component, effectively solves the problem of melt fracture, enables the tensile strength of the PEVA waterproof and vapor-barrier film to reach 12 - 18 MPa, the elongation at break is not less than 500%, and the thickness deviation of the 0.05 - 0.2 mm film is controlled to be less than ±5%. While ensuring good mechanical properties, it also improves the stability during the processing and the consistency of product quality. Detailed Embodiments

[0029] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Apparently, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0030] The embodiments of the present invention provide a PEVA waterproof and vapor-barrier film, which includes the following components by weight: polyethylene-vinyl acetate copolymer: 62 - 78 parts (for example, it can be 62 parts, 64 parts, 65 parts, 68 parts, 70 parts, 72 parts, 74 parts, 75 parts, or 78 parts), toughening agent: 5 - 12 parts (for example, it can be 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, 10 parts, 11 parts, or 12 parts), waterproof and vapor-barrier auxiliary agent: 5 - 10 parts (for example, it can be 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, or 10 parts), antioxidant: 1 - 3 parts (for example, it can be 1 part, 1.5 parts, 2 parts, 2.5 parts, or 3 parts), light stabilizer: 0.5 - 2 parts (for example, it can be 0.5 parts, 1 part, 1.5 parts, or 2 parts), lubricant: 1 - 2 parts (for example, it can be 1 part, 1.5 parts, or 2 parts).

[0031] In the embodiments of the present invention, first, the content of vinyl acetate in the polyethylene-vinyl acetate copolymer is regulated to regulate the properties and compatibility of the polyethylene-vinyl acetate copolymer. Then, a toughening agent, a waterproof and vapor-barrier auxiliary agent, an antioxidant, a light stabilizer, and a lubricant are further added, and the content of each component is regulated. As a result, not only the mechanical properties and waterproof and vapor-barrier properties of the PEVA waterproof and vapor-barrier film are effectively enhanced, achieving "toughening without reducing rigidity", but also the weather resistance of the waterproof and vapor-barrier film is improved. Finally, combined with the gradient temperature control calendering process, each component is uniformly dispersed to form an efficient waterproof and vapor-barrier structure. Through experimental verification, the water vapor transmission rate of the PEVA waterproof and vapor-barrier film in the present invention is less than 1.5 g / m 2· With a hydrostatic pressure resistance greater than 150 kPa for 24 hours, it can effectively prevent the penetration of water vapor, avoid the insulation layer from failing due to moisture, and provide a reliable waterproof and vapor barrier guarantee for the building envelope system.

[0032] According to some preferred embodiments, in the ethylene-vinyl acetate copolymer, the mass content of vinyl acetate is 22-28% (for example, it can be 22%, 23%, 24%, 25%, 26%, 27% or 28%).

[0033] As the base material of PEVA, in the embodiments of the present invention, the content of vinyl acetate in the ethylene-vinyl acetate copolymer is first regulated, so that the molecular chain flexibility of the PEVA resin can be improved, and it has good waterproof and vapor barrier properties, flexibility and processing properties. At the same time, it is also beneficial to the compatibility with other components, and can realize the flexibility regulation of the PEVA waterproof and vapor barrier film from the root.

[0034] According to some preferred embodiments, the toughening agent is at least one of styrene-butadiene-styrene block copolymer, thermoplastic polyurethane elastomer or polyolefin elastomer; the waterproof and vapor barrier auxiliary agent is at least one of silicone waterproof agent, nano-montmorillonite or mica powder; the antioxidant is one of phenolic antioxidant KY-1076, phosphite antioxidant 168, dilauryl thiodipropionate or compound antioxidant Finox B215; the light stabilizer is at least one of 2-hydroxy-4'-methoxybenzophenone, hindered amine light stabilizer HS-944 or phenyl salicylate; the lubricant is at least one of microcrystalline wax, calcium stearate and pentaerythritol stearate.

[0035] In the embodiments of the present invention, by further adding a toughening agent, a waterproof and vapor-barrier aid, an antioxidant, a light stabilizer, and a lubricant to the polyethylene-vinyl acetate copolymer, the comprehensive performance of the PEVA waterproof and vapor-barrier film can be regulated. Among them, the toughening agent of the above type can form an elastic phase or a flexible molecular chain network, and physically entangle with the PEVA molecular chain to form a three-dimensional network, thereby significantly enhancing the toughness and impact resistance of the PEVA waterproof and vapor-barrier film, and reducing the risk of rupture of the PEVA waterproof and vapor-barrier film during use. Moreover, by further adding the waterproof and vapor-barrier aid of the above type, it can cooperate with the toughening agent in the system to enhance the waterproof and vapor-barrier performance of the PEVA film while ensuring toughness from different mechanisms. The silicone waterproof agent can form a hydrophobic layer on the surface of the PEVA film to effectively prevent the penetration of moisture. The nano-montmorillonite has a layered structure and can form tortuous channels in the PEVA film to increase the resistance to water vapor penetration, thereby improving the vapor-barrier performance. The mica powder has a lamellar structure and forms tortuous paths in the PEVA film to effectively block the penetration of water vapor, reduce the water vapor transmission rate of the PEVA film material, and improve the vapor-barrier performance.

[0036] Meanwhile, based on the polyethylene-vinyl acetate copolymer system, a certain type of antioxidant, light stabilizer, and lubricant are further added. The antioxidant can delay the oxidation process of the polyethylene-vinyl acetate copolymer, improve the aging resistance of the PEVA film, and extend the service life of the film. The light stabilizer can absorb the energy of ultraviolet rays, inhibit the degradation effect of ultraviolet rays on the PEVA film, and improve the weather resistance of the film. The addition of the lubricant can not only reduce the friction between the PEVA film and the processing equipment, improve the processing efficiency, but also help to further enhance the toughness of the PEVA film and make the surface of the PEVA film smoother.

[0037] It should be noted that in order to ensure good compatibility between the waterproof and vapor-barrier aid and other components, the waterproof and vapor-barrier aid in the embodiments of the present invention all adopt nano-level particles.

[0038] According to some preferred embodiments, the mass ratio of the waterproof and vapor-barrier aid to the lubricant is (5 - 10):(1 - 2) (for example, it can be 5:1, 6:1, 7:1, 8:1, 9:1, 10:1, 5:2, 6:2, 7:2, 8:2, 9:2, or 10:2); the mass ratio of the antioxidant to the light stabilizer is (1 - 3):(0.5 - 2) (for example, it can be 1:0.5, 1:1, 1:2, 2:0.5, 2:1, 2:2, 3:0.5, 3:1, or 3:2).

[0039] In the embodiments of the present invention, by further controlling the ratio of ethylene-vinyl acetate copolymer to the waterproof and vapor-barrier additive and the lubricant, the lubricant can promote the uniform dispersion of the waterproof and vapor-barrier additive, and the two cooperate with each other, which is beneficial to further enhance the mechanical properties of the PEVA waterproof and vapor-barrier film, achieving the effect of "toughness without sacrificing rigidity"; by compounding antioxidants and light stabilizers, the antioxidant delays the molecular chain breakage caused by thermal oxidation, and the light stabilizer blocks the free radical reaction caused by ultraviolet rays, so that the weather resistance of the PEVA waterproof and vapor-barrier film can be extended jointly from both the aspects of light and heat.

[0040] According to some preferred embodiments, by weight, it comprises the following components: ethylene-vinyl acetate copolymer: 65-75 parts (for example, it can be 65 parts, 68 parts, 70 parts, 72 parts, 74 parts or 75 parts), toughening agent: 8-12 parts (for example, it can be 8 parts, 9 parts, 10 parts, 11 parts or 12 parts), waterproof and vapor-barrier additive: 6-10 parts (for example, it can be 6 parts, 7 parts, 8 parts, 9 parts or 10 parts), antioxidant: 1-3 parts (for example, it can be 1 part, 1.5 parts, 2 parts, 2.5 parts or 3 parts), light stabilizer: 0.5-2 parts (for example, it can be 0.5 parts, 1 part, 1.5 parts or 2 parts), lubricant: 1-2 parts (for example, it can be 1 part, 1.5 parts or 2 parts).

[0041] In the embodiments of the present invention, by the synergistic control of the content of each component, it is beneficial to prepare a PEVA waterproof and vapor-barrier film with good waterproof and vapor-barrier properties, mechanical properties and weather resistance; it is confirmed by the experiments of the present invention that an appropriate content of the toughening agent is beneficial to improving the flexibility and impact resistance of the PEVA waterproof and vapor-barrier film, but if the content of the toughening agent is too high, the elongation at break and the waterproof and vapor-barrier properties of the PEVA waterproof and vapor-barrier film will be reduced. An appropriate content of the waterproof and vapor-barrier additive is beneficial to improving the waterproof and vapor-barrier properties of the PEVA waterproof and vapor-barrier film, but if the content of the waterproof and vapor-barrier additive is too high, it will not only increase the thickness of the PEVA waterproof and vapor-barrier film, but also reduce the compatibility of the additive with other components and is easy to precipitate from the system, thus having an adverse effect on the waterproof and vapor-barrier properties and the elongation at break. And an appropriate content of the antioxidant and the light stabilizer is beneficial to jointly enhancing the weather resistance of the PEVA waterproof and vapor-barrier film. If the content of the light stabilizer and the antioxidant is too high, it will not only lead to an increase in cost, but also may affect the transparency of the PEVA waterproof and vapor-barrier film. Further, if the content of the lubricant is too low, the processing performance of the PEVA film will be reduced, while an excessive amount of lubricant may weaken the interfacial bonding between the toughening agent and the matrix. Therefore, it is necessary to balance the dosage of each component.

[0042] The present invention also provides a preparation method of the PEVA waterproof and vapor-barrier film according to any one of the above, and the preparation method comprises the following steps:

[0043] (1) Mix the polyethylene-vinyl acetate copolymer, toughening agent, waterproof and moisture-proof barrier aid, antioxidant, light stabilizer and lubricant in proportion to obtain a mixed material;

[0044] (2) Add the mixed material into a twin-screw extruder for extrusion granulation to obtain a masterbatch of the mixed material; wherein, the twin-screw extruder includes several zones, and along the direction from the feed port to the discharge port, the temperature gradient of each zone rises;

[0045] (3) Add the masterbatch of the mixed material into a calender for calendering to obtain the PEVA waterproof and moisture-proof barrier film; wherein, the calender includes several working rolls, and along the direction from the feed roll to the discharge roll, the temperature gradient of each working roll decreases and the rotational speed gradient increases.

[0046] According to some preferred embodiments, in step (1), the temperature for mixing is 70 - 80 °C (for example, it can be 70 °C, 72 °C, 75 °C, 78 °C or 80 °C), and the time is 15 - 20 min (for example, it can be 15 min, 16 min, 17 min, 18 min, 19 min or 20 min).

[0047] In the embodiment of the present invention, the weighed components are added into a high-speed mixer and stirred and mixed at a certain temperature. At this time, the polyethylene-vinyl acetate copolymer is in a semi-molten state, which can ensure the preliminary uniform dispersion of each component, lay a foundation for subsequent processing (such as extrusion and calendering), and at the same time can prevent other components from failing.

[0048] According to some preferred embodiments, before step (1), it further includes: the steps of drying the polyethylene-vinyl acetate copolymer and the waterproof and moisture-proof barrier aid respectively; the drying temperature of the polyethylene-vinyl acetate copolymer is 80 - 90 °C (for example, it can be 70 °C, 72 °C, 75 °C, 78 °C or 80 °C), and the time is 2 - 3 h (for example, it can be 2 h, 2.5 h or 3 h); the drying temperature of the waterproof and moisture-proof barrier aid is 100 - 120 °C (for example, it can be 100 °C, 105 °C, 110 °C, 115 °C or 120 °C), and the time is 1 - 2 h (for example, it can be 1 h, 1.5 h or 2 h).

[0049] In the embodiment of the present invention, before mixing, the polyethylene-vinyl acetate copolymer is first dried at the above temperature to remove moisture, so as to prevent bubbles from being generated during the processing and affecting the quality of the PEVA waterproof and moisture-proof barrier film; at the same time, the waterproof and moisture-proof barrier aid is dried and activated at the above temperature to remove the moisture in the waterproof and moisture-proof barrier aid powder and improve its compatibility with other components.

[0050] According to some preferred embodiments, in step (2), the twin-screw extruder includes 5 zones; wherein, the temperature of zone 1 of the twin-screw extruder is 130 - 140 °C (for example, it can be 130 °C, 132 °C, 135 °C, 138 °C or 140 °C), the temperature of zone 2 is 140 - 150 °C (for example, it can be 140 °C, 142 °C, 145 °C, 148 °C or 150 °C), the temperature of zone 3 is 150 - 160 °C (for example, it can be 150 °C, 152 °C, 155 °C, 158 °C or 160 °C), the temperature of zone 4 is 160 - 170 °C (for example, it can be 160 °C, 162 °C, 165 °C, 168 °C or 170 °C), the temperature of the die head is 170 - 180 °C (for example, it can be 170 °C, 172 °C, 175 °C, 178 °C or 180 °C), and the rotational speed of the twin-screw is 180 - 220 r / min (for example, it can be 180 r / min, 190 r / min, 200 r / min, 210 r / min or 220 r / min).

[0051] In the embodiments of the present invention, the mixed material is added to a twin-screw extruder including multiple temperature zones (for example, including 4 temperature zones) for extrusion granulation, and the extruded material is cut into pellets after water cooling to obtain special masterbatch for the mixed material masterbatch. By controlling the temperature of each zone in the twin-screw extruder in a gradient manner according to the melting points of the above-mentioned respective components during the extrusion process, and reasonably controlling the rotational speed of the bolt screw, it is possible to achieve staged melting and uniform mixing of each component, avoid bridging blockage caused by rapid melting at the feed inlet of the twin-screw extruder, ensure continuous and stable feeding, and guarantee good extrusion efficiency and product quality. After completing the extrusion granulation.

[0052] According to some preferred embodiments, in step (3), the calender includes a feeding roller, a first intermediate roller, a second intermediate roller, a final roller, and a cooling roller arranged in sequence; among them, the temperature of the feeding roller is 110 - 130 °C (for example, it can be 110 °C, 120 °C, or 130 °C), and the rotational speed is 8 - 10 rpm (for example, it can be 8 rpm, 9 rpm, or 10 rpm); the temperature of the first intermediate roller is 110 - 120 °C (for example, it can be 110 °C, 115 °C, or 120 °C), and the rotational speed is 10 - 12 rpm (for example, it can be 10 rpm, 11 rpm, or 12 rpm); the temperature of the second intermediate roller is 100 - 110 °C (for example, it can be 100 °C, 105 °C, or 110 °C), and the rotational speed is 12 - 15 rpm (for example, it can be 12 rpm, 13 rpm, 14 rpm, or 15 rpm); the temperature of the final roller is 90 - 100 °C (for example, it can be 90 °C, 95 °C, or 100 °C), and the rotational speed is 18 - 25 rpm (for example, it can be 18 rpm, 19 rpm, 20 rpm, 21 rpm, 22 rpm, 23 rpm, 24 rpm, or 25 rpm); the temperature of the cooling roller is 40 - 60 °C (for example, it can be 40 °C, 50 °C, or 60 °C), and the rotational speed is 25 - 28 rpm (for example, it can be 25 rpm, 26 rpm, 27 rpm, or 28 rpm).

[0053] In the embodiments of the present invention, the mixed material masterbatch is added to the calender for calendering and forming. Based on the melting temperature (90 - 120 °C) of the mixed material masterbatch and the shaping requirements, by gradient setting of the temperatures and rotational speeds of each working roller in the calender, specifically, the temperatures of each working roller starting from the feeding roller are set to decrease in a gradient, and the rotational speeds are set to increase in a gradient. After the mixed material masterbatch enters the feeding roller, through temperature gradient control, the mixed material masterbatch is fully melted and plasticized, facilitating extension. Further, through rotational speed gradient regulation, the melt is gradually extended in a plastic state, avoiding melt fracture, and controlling the slow cooling of the melt, reducing internal stress or warpage deformation caused by sudden cooling. Through the calendering control of the coordinated gradient rotational speed and temperature difference, in this way, it can ensure that the mixed material masterbatch is uniformly plasticized and improve the forming quality of the PEVA waterproof and vapor barrier film.

[0054] In the embodiments of the present invention, during the process of preparing the PEVA waterproof and vapor barrier film, a calendering method with coordinated gradient rotational speed and temperature difference is adopted in the process, which improves the plasticization uniformity of the melt formed by the mixing of each component, effectively solves the problem of melt fracture, enables the tensile strength of the PEVA waterproof and vapor barrier film to reach 12 - 18 MPa, the elongation at break is not less than 500%, and the thickness deviation of the 0.05 - 0.2 mm film is controlled to be less than ±5%. While ensuring good mechanical properties, it also improves the stability during the processing and the consistency of product quality.

[0055] It should be noted that in the embodiments of the present invention, the twin-screw extruder and the calender can adopt the equipment in the prior art.

[0056] In order to more clearly illustrate the technical solutions and advantages of the present invention, a PEVA waterproof and vapor barrier film and its preparation method will be described in detail through several embodiments below;

[0057] In the following embodiments, the polyethylene-vinyl acetate copolymer, the waterproof and vapor barrier additive, the toughening agent, the antioxidant, the light stabilizer, and the lubricant are all expressed in parts by mass.

[0058] Example 1:

[0059] (1) Dry the polyethylene-vinyl acetate copolymer (the content of vinyl acetate is 25 wt%) at 85 °C for 2.5 h, and dry and activate the waterproof and vapor barrier additive (nano-montmorillonite) at 110 °C for 1.5 h to obtain the pretreated polyethylene-vinyl acetate copolymer and waterproof and vapor barrier additive;

[0060] Add 70 parts of the above-mentioned polyethylene-vinyl acetate copolymer (the content of vinyl acetate is 25 wt%), 10 parts of the toughening agent (styrene-butadiene-styrene block copolymer), 8 parts of the above-mentioned waterproof and vapor barrier additive (nano-montmorillonite), 2 parts of the antioxidant (hindered phenol antioxidant KY-1076), 1 part of the light stabilizer (hindered amine light stabilizer HS-944), and 1 part of the lubricant (calcium stearate) into a high-speed mixer according to the ratio and mix evenly at 75 °C for 18 min to obtain a mixed material;

[0061] (2) Add the mixed material into a twin-screw extruder for extrusion granulation. The temperature of the twin-screw extruder is set as follows: the temperature of the first zone is 135 °C, the temperature of the second zone is 145 °C, the temperature of the third zone is 155 °C, the temperature of the fourth zone is 165 °C, and the temperature of the die head is 175 °C. The rotation speed of the twin-screw is 200 r / min. After the extruded material is cooled by water, it is pelletized to obtain a mixed material masterbatch;

[0062] (3) Add the mixed material masterbatch into a calender for calendering to obtain a PEVA waterproof and vapor barrier film; among them, the temperature and rotation speed of the calender rolls are set as follows: the temperature of the feeding roll is 120 °C, the rotation speed is 8 rpm, the temperature of the first intermediate roll is 115 °C, the rotation speed is 11 rpm, the temperature of the second intermediate roll is 105 °C, the rotation speed is 12 rpm, the temperature of the final roll is 95 °C, the rotation speed is 20 rpm, and the temperature of the cooling roll is 50 °C, the rotation speed is 25 rpm.

[0063] Example 2:

[0064] (1) Dry the polyethylene-vinyl acetate copolymer (with a vinyl acetate content of 22 wt%) at 80 °C for 2 h, and dry and activate the waterproof and moisture-vapor barrier aid (organosilicon waterproof agent) at 100 °C for 2 h to obtain the pretreated polyethylene-vinyl acetate copolymer and the waterproof and moisture-vapor barrier aid;

[0065] Add 65 parts of the above polyethylene-vinyl acetate copolymer (with a vinyl acetate content of 22 wt%), 12 parts of a toughening agent (thermoplastic polyurethane elastomer), 10 parts of the above waterproof and moisture-vapor barrier aid (organosilicon waterproof agent), 3 parts of an antioxidant (phosphite antioxidant 168), 2 parts of a light stabilizer (2-hydroxy-4'-methoxybenzophenone), and 2 parts of a lubricant (microcrystalline wax) into a high-speed mixer according to the ratio and mix evenly at 70 °C for 20 min to obtain a mixed material;

[0066] (2) Add the mixed material into a twin-screw extruder for extrusion granulation. The temperature of the twin-screw extruder is set as follows: the temperature of zone 1 is 130 °C, the temperature of zone 2 is 140 °C, the temperature of zone 3 is 150 °C, the temperature of zone 4 is 160 °C, and the temperature of the die head is 170 °C. The rotation speed of the twin-screw is 180 r / min. After the extruded material is cooled by water, it is pelletized to obtain the masterbatch of the mixed material;

[0067] (3) Add the masterbatch of the mixed material into a calender for calendering to obtain the PEVA waterproof and moisture-vapor barrier film; among them, the temperature and rotation speed of the calender rolls are set as follows: the temperature of the feeding roll is 122 °C, the rotation speed is 8 rpm, the temperature of the first intermediate roll is 118 °C, the rotation speed is 12 rpm, the temperature of the second intermediate roll is 105 °C, the rotation speed is 13 rpm, the temperature of the final roll is 100 °C, the rotation speed is 22 rpm, and the temperature of the cooling roll is 55 °C, the rotation speed is 26 rpm.

[0068] Example 3:

[0069] (1) Dry the polyethylene-vinyl acetate copolymer (with a vinyl acetate content of 28 wt%) at 90 °C for 2 h, and dry and activate the waterproof and moisture-vapor barrier aid (mica powder) at 120 °C for 1 h to obtain the pretreated polyethylene-vinyl acetate copolymer and the waterproof and moisture-vapor barrier aid;

[0070] Add 75 parts of the above polyethylene-vinyl acetate copolymer (with a vinyl acetate content of 28 wt%), 8 parts of a toughening agent (polyolefin elastomer), 6 parts of the above waterproof and moisture-vapor barrier aid (mica powder), 1 part of an antioxidant (dilauryl thiodipropionate), 1 part of a light stabilizer (phenyl salicylate), and 1 part of a lubricant (pentaerythritol stearate) into a high-speed mixer according to the ratio and mix evenly at 80 °C for 15 min to obtain a mixed material;

[0071] (2) Add the mixed materials into a twin-screw extruder for extrusion granulation. The temperature settings of the twin-screw extruder are as follows: the temperature of zone 1 is 140 °C, the temperature of zone 2 is 150 °C, the temperature of zone 3 is 160 °C, the temperature of zone 4 is 170 °C, and the temperature of the die head is 180 °C. The rotational speed of the twin-screw is 200 r / min. After the extruded material is cooled by water, it is pelletized to obtain the masterbatch of the mixed materials;

[0072] (3) Add the masterbatch of the mixed materials into a calender for calendering to obtain the PEVA waterproof and vapor-barrier film. Among them, the temperature and rotational speed of the calender rolls are set as follows: the temperature of the feeding roll is 130 °C and the rotational speed is 10 rpm, the temperature of the first intermediate roll is 120 °C and the rotational speed is 11 rpm, the temperature of the second intermediate roll is 105 °C and the rotational speed is 15 rpm, the temperature of the final roll is 98 °C and the rotational speed is 25 rpm, and the temperature of the cooling roll is 50 °C and the rotational speed is 28 rpm.

[0073] Example 4:

[0074] (1) Dry the polyethylene-vinyl acetate copolymer (the content of vinyl acetate is 25 wt%) at 85 °C for 2.5 h, and dry and activate the waterproof and vapor-barrier additive (nano-montmorillonite) at 110 °C for 1.5 h to obtain the pretreated polyethylene-vinyl acetate copolymer and waterproof and vapor-barrier additive;

[0075] Add 80 parts of the above polyethylene-vinyl acetate copolymer (the content of vinyl acetate is 25 wt%), 10 parts of the toughening agent (polyolefin elastomer), 6 parts of the above waterproof and vapor-barrier additive (nano-montmorillonite), 2 parts of the antioxidant (hindered phenol antioxidant KY-1076), 1 part of the light stabilizer (hindered amine light stabilizer HS-944), and 2 parts of the lubricant (calcium stearate) into a high-speed mixer in proportion and mix evenly at 75 °C for 18 min to obtain the mixed materials;

[0076] (2) Add the mixed materials into a twin-screw extruder for extrusion granulation. The temperature settings of the twin-screw extruder are as follows: the temperature of zone 1 is 140 °C, the temperature of zone 2 is 145 °C, the temperature of zone 3 is 160 °C, the temperature of zone 4 is 165 °C, and the temperature of the die head is 180 °C. The rotational speed of the twin-screw is 200 r / min. After the extruded material is cooled by water, it is pelletized to obtain the masterbatch of the mixed materials;

[0077] (3) Add the masterbatch of the mixed materials into a calender for calendering to obtain the PEVA waterproof and vapor-barrier film. Among them, the temperature and rotational speed of the calender rolls are set as follows: the temperature of the feeding roll is 125 °C and the rotational speed is 8 rpm, the temperature of the first intermediate roll is 120 °C and the rotational speed is 12 rpm, the temperature of the second intermediate roll is 110 °C and the rotational speed is 15 rpm, the temperature of the final roll is 95 °C and the rotational speed is 18 rpm, and the temperature of the cooling roll is 60 °C and the rotational speed is 25 rpm.

[0078] Example 5:

[0079] (1) Dry the polyethylene-vinyl acetate copolymer (with a vinyl acetate content of 22 wt%) at 80 °C for 3 h, and dry and activate the waterproof and moisture-vapor barrier aid (silicone waterproof agent) at 100 °C for 2 h to obtain the pretreated polyethylene-vinyl acetate copolymer and waterproof and moisture-vapor barrier aid;

[0080] Add 60 parts of the above polyethylene-vinyl acetate copolymer (with a vinyl acetate content of 22 wt%), 8 parts of toughening agent (thermoplastic polyurethane elastomer), 6 parts of the above waterproof and moisture-vapor barrier aid (silicone waterproof agent), 2 parts of antioxidant (phosphite antioxidant 168), 0.5 part of light stabilizer (2-hydroxy-4'-methoxybenzophenone), and 2 parts of lubricant (microcrystalline wax) to a high-speed mixer in proportion and mix evenly at 70 °C for 20 min to obtain a mixed material;

[0081] (2) Add the mixed material to a twin-screw extruder for extrusion granulation. The temperature settings of the twin-screw extruder are: the temperature of zone 1 is 135 °C, the temperature of zone 2 is 150 °C, the temperature of zone 3 is 155 °C, the temperature of zone 4 is 170 °C, the temperature of the die head is 175 °C, the rotation speed of the twin-screw is 180 r / min. After the extruded material is cooled by water, it is pelletized to obtain a mixed material masterbatch;

[0082] (3) Add the mixed material masterbatch to a calender for calendering to obtain a PEVA waterproof and moisture-vapor barrier film; among them, the temperature and rotation speed of the calender rolls are set as follows: the temperature of the feeding roll is 125 °C, the rotation speed is 10 rpm, the temperature of the first intermediate roll is 120 °C, the rotation speed is 12 rpm, the temperature of the second intermediate roll is 105 °C, the rotation speed is 14 rpm, the temperature of the final roll is 95 °C, the rotation speed is 20 rpm, and the temperature of the cooling roll is 60 °C, the rotation speed is 25 rpm.

[0083] Example 6:

[0084] (1) Dry the polyethylene-vinyl acetate copolymer (with a vinyl acetate content of 28 wt%) at 90 °C for 2 h, and dry and activate the waterproof and moisture-vapor barrier aid (mica powder) at 120 °C for 1 h to obtain the pretreated polyethylene-vinyl acetate copolymer and waterproof and moisture-vapor barrier aid;

[0085] Add 90 parts of the above polyethylene-vinyl acetate copolymer (with a vinyl acetate content of 28 wt%), 10 parts of toughening agent (polyolefin elastomer), 10 parts of the above waterproof and moisture-vapor barrier aid (mica powder), 1 part of antioxidant (dilauryl thiodipropionate), 1 part of light stabilizer (phenyl salicylate), and 1.5 parts of lubricant (pentaerythritol stearate) to a high-speed mixer in proportion and mix evenly at 80 °C for 15 min to obtain a mixed material;

[0086] (2) Add the mixed materials into a twin-screw extruder for extrusion granulation. The temperature settings of the twin-screw extruder are as follows: the temperature of the first zone is 140 °C, the second zone is 145 °C, the third zone is 150 °C, the fourth zone is 160 °C, and the head temperature is 175 °C. The rotation speed of the twin-screw is 220 r / min. After the extruded material is cooled by water, it is pelletized to obtain the masterbatch of the mixed materials.

[0087] (3) Add the masterbatch of the mixed materials into a calender for calendering to obtain a PEVA waterproof and vapor-barrier film. Among them, the temperature and rotation speed of the calender rolls are set as follows: the temperature of the feeding roll is 130 °C and the rotation speed is 10 rpm, the temperature of the first intermediate roll is 125 °C and the rotation speed is 12 rpm, the temperature of the second intermediate roll is 110 °C and the rotation speed is 14 rpm, the temperature of the final roll is 100 °C and the rotation speed is 22 rpm, and the temperature of the cooling roll is 60 °C and the rotation speed is 25 rpm.

[0088] Example 7:

[0089] Example 7 is basically the same as Example 1, except that in step (1), the waterproof and vapor-barrier aid is 15 parts.

[0090] Example 8:

[0091] Example 8 is basically the same as Example 1, except that in step (1), the toughening agent is 15 parts.

[0092] Example 9:

[0093] Example 9 is basically the same as Example 1, except that in step (1), the lubricant is 5 parts.

[0094] Comparative Example 1:

[0095] Comparative Example 1 is basically the same as Example 1, except that in step (1), no waterproof and vapor-barrier aid is added, and only the polyethylene-vinyl acetate copolymer, toughening agent, antioxidant, light stabilizer and lubricant are mixed evenly to obtain the mixed materials.

[0096] Comparative Example 2:

[0097] Comparative Example 2 is basically the same as Example 1, except that the toughening agent in step (1) is replaced with the same mass fraction of plasticizer (dioctyl phthalate).

[0098] Comparative Example 3:

[0099] Comparative Example 3 is basically the same as Example 1, except that in step (2), the temperature settings of the twin-screw extruder are as follows: the temperature of the first zone is 150 °C, the temperature of the second zone is 150 °C, the temperature of the third zone is 150 °C, the temperature of the fourth zone is 150 °C, the temperature of the die head is 175 °C, the rotational speed of the twin-screw is 200 r / min, and the extruded material is granulated after water cooling to obtain a masterbatch of the mixed material.

[0100] Comparative Example 4:

[0101] Comparative Example 4 is basically the same as Example 1, except that in step (3), the temperature and rotational speed of the calender rolls are set as follows: the temperature of the feeding roll is 120 °C and the rotational speed is 10 rpm, the temperature of the first intermediate roll is 115 °C and the rotational speed is 10 rpm, the temperature of the second intermediate roll is 105 °C and the rotational speed is 10 rpm, the temperature of the final roll is 95 °C and the rotational speed is 10 rpm, and the temperature of the cooling roll is 50 °C and the rotational speed is 10 rpm.

[0102] The PEVA waterproof and vapor-barrier films (hereinafter referred to as samples) prepared in Examples 1 to 9 and Comparative Examples 1 to 4 were subjected to performance tests, and the test results are shown in Table 1.

[0103] Tensile strength test:

[0104] Cut a specimen with appropriate size and shape from the material to be tested, ensure that the surface of the specimen is smooth, without obvious defects, cracks or damages, and measure the initial dimensions of the specimen, including the gauge length, width, thickness, etc.; install the specimen in the fixture of the tensile testing machine, ensure that the axis of the specimen coincides with the tensile axis of the testing machine to ensure that the tensile force is evenly applied to the specimen; according to the characteristics of the material and the test requirements, set the test parameters of the tensile testing machine, such as the tensile speed, loading range, etc.; start the tensile testing machine, apply a gradually increasing tensile force to the specimen to make the specimen gradually elongate until it breaks; during the test, record the maximum tensile force value when the specimen breaks, as well as the corresponding elongation and other relevant data; finally, according to the initial cross-sectional area and the maximum tensile force of the specimen, calculate the tensile strength according to the formula: Tensile strength = Maximum tensile force / Initial cross-sectional area of the specimen.

[0105] Elongation at break test:

[0106] Process the specimen into the specified shape and size, ensuring that the surface of the specimen is smooth and defect-free. Mark the original gauge length on the specimen (the gauge length refers to the specific length range used to measure the elongation in a tensile test. Usually, two punctuation marks are marked on the specimen, and the distance between the two punctuation marks is the original gauge length, generally denoted as L0); Install the specimen in the fixture of the tensile testing machine, ensuring that the axis of the specimen coincides with the tensile axis of the testing machine to ensure that the tensile force acts uniformly on the specimen; Start the tensile testing machine, apply a gradually increasing tensile force to the specimen, causing the specimen to gradually elongate until it breaks; During the test, record the elongation of the specimen and the corresponding tensile force data. When the specimen breaks, record the elongation data at the moment of fracture; Carefully remove the fractured specimen, align the two fractured parts, try to restore it to the state before fracture, and use a measuring tool to measure the distance between the two punctuation marks after fracture, denoted as L1. If the fracture is close to the punctuation mark, it may be necessary to make corrections according to the regulations of relevant standards.

[0107] Calculate the elongation at break δ according to the formula:

[0108] δ = (L1 - L0) / L0 × 100%, and the calculated result is the elongation at break of the material.

[0109] Hydrostatic pressure resistance test:

[0110] According to the test standards and requirements, cut a sufficient number of specimens (5) from the material to be tested. The size of the specimens is usually circular or square, and the diameter or side length is generally between 100 - 200 mm; Place the cut specimens under standard temperature and humidity conditions for a certain period of time to reach a stable state. Generally, the temperature is controlled at (20 ± 2) °C, the relative humidity is controlled at (65 ± 5)%, and the placement time is not less than 24 hours. Install the prepared specimens flatly on the specimen fixture of the hydrostatic pressure resistance tester, ensuring good sealing between the specimens and the fixture without leakage. Auxiliary sealing materials such as sealing rings or sealants can be used; Start the hydrostatic pressure resistance tester, slowly and uniformly apply water pressure to one side of the specimen, generally 10 - 50 kPa per minute; During the process of applying water pressure, closely observe the situation on the other side of the specimen. When the first drop of water seeps out or obvious water penetration occurs on the surface of the specimen, record the water pressure value at this time, which is the hydrostatic pressure resistance value of the specimen. Repeat the test: Conduct the same test on multiple specimens to obtain more accurate and representative test results. Calculate statistical data such as the average value, maximum value, and minimum value of the hydrostatic pressure resistance of the 5 specimens.

[0111] Air permeability test: Refer to GB / T 1038 "Test Method for Gas Permeability of Plastic Films and Sheets - Differential Pressure Method".

[0112] Table 1

[0113]

[0114]

[0115] In the embodiment of the present invention, the formula of the PEVA waterproof vapor barrier film is regulated, and the gradient temperature control extrusion process is combined to make the components and fillers evenly dispersed, and the calendering process of the gradient speed and temperature difference is further combined to form a PEVA waterproof vapor barrier film with excellent performance. It can be seen from Table 1 that the PEVA waterproof vapor barrier film in the embodiment of the present invention has the characteristics of thin thickness, excellent waterproof vapor barrier performance and excellent mechanical properties, with a thickness of only 0.05-0.2mm, and a water vapor permeability of less than 1.5g / m 2 ·24h, hydrostatic pressure resistance greater than 150kPa, the tensile strength of the PEVA waterproof vapor barrier membrane reaches 12-18MPa, the elongation at break is not less than 500%, and the thickness deviation of the 0.05-0.2mm film is controlled within ±5%. While ensuring good mechanical properties, it also improves the stability of the processing process and the consistency of product quality, and has excellent waterproof and vapor barrier effects in building doors and windows.

[0116] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A PEVA waterproof and vapor barrier film, characterized in that, By weight parts, it comprises the following components: polyethylene-vinyl acetate copolymer: 62-78 parts, toughening agent: 5-12 parts, waterproof and moisture-vapor barrier aid: 5-10 parts, antioxidant: 1-3 parts, light stabilizer: 0.5-2 parts, lubricant: 1-2 parts.

2. The waterproof and vapor barrier film according to claim 1, wherein In the polyethylene-vinyl acetate copolymer, the mass content of vinyl acetate is 22-28%.

3. The waterproof and vapor barrier film according to claim 1, characterized in that, The toughening agent is at least one of styrene-butadiene-styrene block copolymer, thermoplastic polyurethane elastomer or polyolefin elastomer; The waterproof and moisture-vapor barrier aid is at least one of silicone waterproof agent, nano-montmorillonite or mica powder; The antioxidant is one of hindered phenol antioxidant KY-1076, phosphite antioxidant 168, dilauryl thiodipropionate or compound antioxidant Finox B215; The light stabilizer is at least one of 2-hydroxy-4'-methoxybenzophenone, hindered amine light stabilizer HS-944 or phenyl salicylate; The lubricant is at least one of microcrystalline wax, calcium stearate and pentaerythritol stearate.

4. The waterproof and vapor-barrier film according to claim 1, wherein The mass ratio of the waterproof and moisture-vapor barrier aid to the lubricant is (5-10):(1-2); and / or The mass ratio of the antioxidant to the light stabilizer is (1-3):(0.5-2).

5. The waterproof and vapor barrier film according to claim 1, characterized in that, By weight parts, it comprises the following components: polyethylene-vinyl acetate copolymer: 65-75 parts, toughening agent: 8-12 parts, waterproof and moisture-vapor barrier aid: 6-10 parts, antioxidant: 1-3 parts, light stabilizer: 0.5-2 parts, lubricant: 1-2 parts.

6. A method for preparing a PEVA waterproof and vapor barrier film according to any one of claims 1 to 5, characterized in that, The preparation method comprises the following steps: (1) Mix the polyethylene-vinyl acetate copolymer, toughening agent, waterproof and moisture-vapor barrier aid, antioxidant, light stabilizer and lubricant in proportion to obtain a mixed material; (2) Add the mixed material into a twin-screw extruder for extrusion granulation to obtain a masterbatch of the mixed material; wherein, the twin-screw extruder comprises several zones, and along the direction from the feed inlet to the discharge outlet, the temperature of each zone rises in a gradient manner; (3) Add the masterbatch of the mixed material into a calender for calendering to obtain the PEVA waterproof and moisture-vapor barrier film; wherein, the calender comprises several working rolls, and along the direction from the feed roll to the discharge roll, the temperature of each working roll decreases in a gradient manner and the rotation speed increases in a gradient manner.

7. The preparation method according to claim 6, characterized in that, Before step (1), it further comprises the step of drying the polyethylene-vinyl acetate copolymer and the waterproof and moisture-vapor barrier aid respectively; Preferably, the drying temperature of the polyethylene-vinyl acetate copolymer is 80-90°C and the time is 2-3 h; More preferably, the drying temperature of the waterproof and moisture-vapor barrier aid is 100-120°C and the time is 1-2 h.

8. The preparation method according to claim 6, characterized in that, In step (1), the temperature of mixing is 70-80°C and the time is 15-20 min.

9. The preparation method according to claim 6, characterized in that, In step (2), the twin-screw extruder comprises 5 zones; among them, the temperature of zone 1 of the twin-screw extruder is 130 - 140 °C, the temperature of zone 2 is 140 - 150 °C, the temperature of zone 3 is 150 - 160 °C, the temperature of zone 4 is 160 - 170 °C, the temperature of the head is 170 - 180 °C, and the rotational speed of the twin-screws is 180 - 220 r / min.

10. The preparation method according to claim 6, characterized in that, In step (3), the calender comprises a feeding roller, a first intermediate roller, a second intermediate roller, a final roller and a cooling roller which are arranged in sequence; among them, the temperature of the feeding roller is 110 - 130 °C and the rotational speed is 8 - 10 rpm; the temperature of the first intermediate roller is 110 - 120 °C and the rotational speed is 10 - 12 rpm; the temperature of the second intermediate roller is 100 - 110 °C and the rotational speed is 12 - 15 rpm; the temperature of the final roller is 90 - 100 °C and the rotational speed is 18 - 25 rpm; the temperature of the cooling roller is 40 - 60 °C and the rotational speed is 25 - 28 rpm.

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