A kind of TPU sheet foaming process
Technical field
The present invention relates to technical field of polymer preparation, and in particular to a kind of TPU sheet foaming process.
Background technique
TPU (Thermoplastic polyurethanes) entitled thermoplastic polyurethane elastomer rubber, is between rubber
A kind of high molecular material of glue and plastics, TPU have high-modulus, high intensity, high drawing and high resiliency, and hardness range is wide
(60HA-85HD), wear-resisting, oil resistant, ageing-resistant, transparent, elasticity is good, leads in daily necessities, sports goods, toy, ornament materials etc.
It is used widely in domain.
TPU material is foamed to obtain the TPU material of fretting map by physics or chemical method, has widened TPU material
The application field of material has been increasingly subject to the attention of people.Traditional TPU foaming technique is built bridge with peroxide, then with chemistry
Foaming agent foam forms the foamed material of independent foam.Foaming agent consumption is big, and foaming agent can not recycle, and processes
Complexity, the high requirements on the equipment, harmful to environment, production waste is more.
The patent of invention of notification number CA107793586N specifically discloses TPU foaming materials technique, includes the following steps object
Expect preparation stage, foaming stages, wherein foaming stages include supercritical fluid pressurization, pressure maintaining and unload foam, supercritical fluid
It is pressurised into and TPU material particles is forced into saturation stabilization through supercritical fluid;Pressure maintaining is that pressure maintaining obtains pressurization material after stablizing;Release
For the material that will pressurize, heated foaming obtains expanded beads again after release for foaming, and wherein foamable is in temperature 70 C -180
DEG C, foamed time 1-10min.Technical solution of the present invention can overcome TPU raw material weight is big, hardness is high, damping performance is poor etc.
The shortcomings that aspect, foamed products have environmentally protective, high abrasion folding resistance, light weight, high resiliency, hydrolytic Resistance, anti-chemistry
Moral character energy, oil-resistant characteristic, anti-ultraviolet property, application are good.
Above-mentioned patent is mainly used for making TPU granule foaming material using TPU foaming materials technique, if downstream manufacturers are wanted
Make insole, it is also necessary to TPU expanded beads are subjected to compression molding production, process is tedious, and production efficiency is low, product quality without
Method control.
Summary of the invention
To solve the above-mentioned problems, the present invention provides a kind of TPU sheet foaming process, using supercritical CO2With overcritical N2
The directly obtained TPU sheet material of the infiltration technique foaming combined, the product flatness and plumpness made using this technique
Well, phenomena such as being not in crimping, provides production convenience for downstream manufacturers, and the equipment for greatly reducing downstream manufacturers is thrown
Enter.
In order to achieve the goal above, a kind of technical solution that the present invention takes is:
A kind of TPU sheet foaming process includes the following steps: prepared by sheet material, TPU raw material is heated to molten condition, by adding
Thermoforming is prepared into TPU raw sheet;Shearing, the TPU raw sheet is sheared according to design requirement, obtains the first TPU plate;Leaching
Profit, the first TPU plate is placed in autoclave and is sealed, supercritical CO is passed through in autoclave2It is 8- to pressure
30MPa, and it is warming up to 50-85 DEG C, by CO after pressure maintaining constant temperature 1.5-5h2Fast evacuation;Overcritical N is passed through in autoclave later2
It is 5-20MPa to pressure, and is warming up to 50-85 DEG C, by N after pressure maintaining constant temperature 0.5-2h2Fast evacuation;By described after swelling
One TPU plate takes out to obtain the 2nd TPU plate out of autoclave;And foaming, the 2nd TPU plate is placed in 80-120 DEG C
TPU sheet material after 0.5-10min foams to foam in thermostatic equipment.
Further, the TPU raw material hardness is 70-90A, and isocyanate group and hydroxyl molar ratio are 0.995-0.998.
Further, further include following steps after the foaming step: the TPU sheet drying is placed on close by pressure maintaining
Pressure maintaining is handled in the high-pressure bottle closed.
Further, the pressure holding step is to be passed through CO into the high-pressure bottle2And/or N2To the pressure of 1-5MPa, pressure maintaining
Time 15-26h.
Further, the pressure holding step is passed through the CO in the high-pressure bottle2And N2Ratio be 0.5:1-2:1.
Further, further include following steps after the pressure holding step: fretting map, by the TPU sheet material in thermostatic equipment
Middle fretting map processing.
Further, the fretting map step is that the TPU sheet material is put into 15-30s, 40- in 85-98 DEG C of thermostatic equipment
50 DEG C of low temperature drying 30min.
Further, the thermostatic equipment is one of water-bath, steam, hot wind and oil bath equipment.
Further, the pressure-bearing of the autoclave is greater than 30MPa, and the pressure-bearing of the high-pressure bottle is less than 5MPa.
Further, the dynamic compression shrinking percentage of the TPU sheet material is 0.72-0.78%, static compress shrinking percentage 19.2-
19.6%。
The above technical solution of the present invention has the following advantages over the prior art:
(1) a kind of TPU sheet foaming process of the invention, directly foamed preparation TPU sheet material using TPU plate, avoids downstream
Compression molding prepares the complicated technology of TPU sheet material after manufacturer's purchase TPU expanded beads, and the production for greatly reducing downstream manufacturers is set
Standby investment, improves production efficiency.Since preparation process is carried out by technical professional, produced using the sheet material of this technique preparation
The better qualities such as product flatness, plumpness are not in the technical problems such as crimping, fold.
(2) a kind of TPU sheet foaming process of the invention, using being infiltrated in supercritical fluid kettle, the outer foam process of kettle, with
Foam process is compared in kettle, and the size of autoclave no longer plays a decisive role to the size of production quantity, produces identical quantity
TPU sheet material, the technology high-voltage kettle cavity size that foams outside kettle can reduce the 1/10-1/ of foaming machine autoclave cavity in kettle
5, the TPU sheet material of quantity identical as foam process in prior art kettle can be produced using lesser autoclave, because of autoclave
The maintenance of the bigger equipment of size and manufacturing cost are bigger, therefore the method greatly reduces TPU foaming machine cost.
(3) a kind of TPU sheet foaming process of the invention, if infiltration individually uses supercritical CO in the kettle2Infiltration hair
The TPU sheet material can generate serious curling after bubble, and the flatness of final products is poor.And individually use overcritical N2Infiltration,
Due to N2It is difficult to permeate in TPU material, causes foaming difficult.Using supercritical CO2Infiltration and overcritical N2Infiltrate two kinds of techniques
The infiltration technique combined, supercritical CO2After infiltration, then use overcritical N2Infiltration, N2It can replace in TPU apparent pore
CO2, stablize the CO2 nuclei of bubbles being saturated in the first TPU plate, when preventing from entering foaming step, nuclei of bubbles, which is quickly grown up, to be caused
The problems such as first TPU plate collapses, crimps, bulge, TPU sheet material after making final obtainable foaming is smooth, full, hole of holding one's breath
Rate is higher, edge is straight, and resilience performance is preferable.
(4) a kind of TPU sheet foaming process of the invention, the pressure holding step are located at after the outer foam process of kettle, foaming
Due to release rapidly after the completion of technique, if not using subsequent pressure maintaining technique, the TPU sheet material will appear after 6-8h
Collapse phenomenon and follow the string, foaming after the completion of TPU sheet material is placed in pressure maintaining in high-pressure bottle immediately, can be effectively prevented
Between TPU sheet material the problems such as pullling, collapse, crimping so that the structure of TPU sheet material is more stable.
(5) a kind of TPU sheet foaming process of the invention, the TPU sheet material after pressure maintaining are easy to generate wrinkle, rebound etc. now
As fretting map can prevent the generation of these problems, so that the TPU material after foaming is more full.
(6) a kind of TPU sheet foaming process of the invention, the pressure-bearing of the high-pressure bottle used in the pressure maintaining period
Less than 5MPa, do not need bearing capacity is higher, equipment cost higher autoclave can stable foaming TPU sheet material after expanding
Performance significantly reduces TPU sheet material manufacturing cost.
(7) a kind of TPU sheet foaming process of the invention, water-bath, oil bath, hot wind and steam constant temperature equipment can make
2nd TPU plate is heated evenly during foaming, and acquisition foaming is completely, cell density is big, cell diameter is small, performance is stable
TPU sheet material.
Detailed description of the invention
With reference to the accompanying drawing, by the way that detailed description of specific embodiments of the present invention, technical solution of the present invention will be made
And its advantages are apparent.
Fig. 1 show the flow chart of the TPU sheet foaming process of one embodiment of the invention.
Specific embodiment
Following will be combined with the drawings in the embodiments of the present invention, and technical solution in the embodiment of the present invention carries out clear, complete
Site preparation description, it is clear that described embodiments are only a part of the embodiments of the present invention, instead of all the embodiments.It is based on
Embodiment in the present invention, those skilled in the art's every other implementation obtained without creative efforts
Example, shall fall within the protection scope of the present invention.
In the present embodiment, a kind of TPU sheet foaming process is provided.As shown in Figure 1, the TPU sheet foaming process packet
Include following steps: TPU raw material is heated to molten condition, is prepared into TPU raw sheet by hot briquetting by the preparation of S10 sheet material;S20
Shearing, the TPU raw sheet is sheared according to design requirement, obtains the first TPU plate;S30 infiltration, by the first TPU plate
Material is placed in autoclave and seals, and supercritical CO is passed through in autoclave2It is 8-30MPa to pressure, and is warming up to 50-85 DEG C,
By CO after pressure maintaining constant temperature 1.5-5h2Fast evacuation;Overcritical N is passed through in autoclave later2It is 5-20MPa to pressure, and heats up
To 50-85 DEG C, by N after pressure maintaining constant temperature 0.5-2h2Fast evacuation;The first TPU plate after swelling is taken out of autoclave
Go out to obtain the 2nd TPU plate;The 2nd TPU plate is placed in 0.5-10min in 80-120 DEG C of thermostatic equipment and sent out by S40 foaming
TPU sheet material after steeping to foam;The TPU sheet drying is placed on pressure maintaining in closed high-pressure bottle and handled by S50 pressure maintaining.
S60 fretting map, by the TPU sheet material, fretting map is handled in thermostatic equipment.
Any pure material, with the variation of temperature, pressure, can all be rendered as accordingly solid-state, liquid and gaseous state this
Three kinds of states, the referred to as tri-state of substance.The temperature and pressure value of mutual inversion of phases is called three phase point, every kind of chemical property between tri-state
Stable substance all has an intrinsic critical point, i.e., in the temperature and pressure density of substance and its be in liquid
Shi Midu is close, but remains the speciality of gas.When temperature and pressure has been more than the temperature and pressure of critical point, the object
Matter has entered supercriticality, and the substance under supercriticality not only non-pneumatic but also aneroid state are called supercritical fluid.
Although there are many substance that can be used as supercritical fluid, from cheap and easy to get, critical-temperature and pressure lower, evaporation latent heat compared with
Low, safety and environmental protection etc. considers that the solvent of only only a few meets the requirements.CO2Critical-temperature (31.27 DEG C) and big temperature
Spend it is close, be suitable near room temperature realize operate, critical pressure is only 7.37MPa, and equipment requirement is not high, and CO2Colourless, nothing
Taste, nontoxic, stable chemical performance, manufacturing cost is low, CO in a supercritical state2It can dissolve in TPU, therefore this reality
It applies example and selects supercritical CO2Fluidal infiltration.
Polymer micro foamed material refer to cell diameter be 1-10um, cell density 109-1012A .cm-3It is novel
Material.The present embodiment foam theory is to utilize supercritical CO2It penetrates into inside TPU and reaches saturation state, then fast pressure relief, In
Material internal forms nuclei of bubbles, and being then brought rapidly up makes nuclei of bubbles grow up and be formed, and TPU sheet material is made.The process experienced
The formation of TPU- gas homogenous system, the formation of nuclei of bubbles, nuclei of bubbles 4 stages of sizing grown up with nuclei of bubbles.
The preparation of step S10 sheet material, not all TPU raw material can foam, so will be to TPU in sheet material preparation
Material is selected, and the hardness of selected TPU raw material is 70-90A, and isocyanate group and hydroxyl molar ratio are 0.995-
0.998.Selected TPU raw material is heated to molten condition, TPU raw sheet is prepared by hot briquetting.
S20 shearing, limitation of the size and client for the autoclave that impregnation process uses to final products size determine
It needs to shear TPU raw sheet before being infiltrated, obtains the first TPU plate;Scissors can be used in the shear history, laser is cut
It cuts and cutting equipment etc. carries out.
S30 infiltration.In order to guarantee supercritical CO in the first TPU plate impregnation process2It can realize as soon as possible and be saturated and mention
High efficiency, it usually needs the first TPU plate cut is placed on dedicated supporter, to prevent needs from infiltrating
First TPU plate, which stacks, influences effect of impregnation.Then the supporter for being placed with the first TPU plate is placed in the autoclave
And it seals.Supercritical CO2The key of infiltration is supercritical CO2Fluid penetrates into the first TPU plate and in the first TPU plate
At nuclei of bubbles, CO2Diffusion velocity has played decisive action.The viscosity of supercritical fluid, the relevant performance of solvability isodensity are all
It can be controlled by adjusting pressure.In order to reduce the time of solution formation as far as possible, shortens into nuclear cycle, usually can choose
Increasing gas content is the method for being pressurized and improving temperature.Pressure of the present embodiment in autoclave can be 8-30MPa range
Interior any value, preferably 8MPa, 10 MPa, 15 MPa, 18 MPa, 20 MPa, 23 MPa, 25 MPa, 28 MPa and
30MPa.The pressure-bearing of autoclave is greater than 30Mpa.50-85 DEG C is warming up in autoclave, because high-pressure bottle bearing capacity is higher, sets
The standby bigger equipment manufacturing costs of volume and maintenance cost are bigger, therefore we select the outer foam process of kettle, that is, avoid the first TPU plate
Material foams in autoclave, therefore temperature during infiltration in autoclave is unsuitable excessively high, can be appointing in 50-85 DEG C
One temperature value, preferably 50 DEG C, 52 DEG C, 54 DEG C, 55 DEG C, 57 DEG C, 60 DEG C, 65 DEG C, 68 DEG C, 70 DEG C, 75 DEG C, 78 DEG C, 80 DEG C and
85℃.To, by CO2 fast evacuation, making CO in the first TPU plate after autoclave constant temperature and pressure 1.5-5h2Infiltration reach saturation and
The first TPU board cavity is at nuclei of bubbles.It is preferred that the constant temperature and pressure time be 1.5h, 2h, 2.5h, 3h, 3.5h, 4h, 4.5h with
And 5h.
Individually use supercritical CO2Although infiltration infiltration multiplying power can achieve 5-9 times, after the first TPU plate foaming
Phenomena such as TPU sheet material is easy to happen edge curl, sheet surface out-of-flatness and foaming are uneven, resilience performance is poor.This reality
Apply the preferred supercritical CO of example2The method for combining infiltration with overcritical N2.Supercritical CO2It is passed through in autoclave after infiltration overcritical
N2 is any pressure value in 5-20MPa to pressure, and preferably pressure is 5MPa, 8MPa, 10 MPa, 12 MPa, 15 MPa, 18
MPa and 20 MPa, and it is warming up to any temperature value in 50-85 DEG C, preferably 50 DEG C, 55 DEG C, 57 DEG C, 60 DEG C, 65 DEG C, 68
DEG C, 70 DEG C, 75 DEG C, 78 DEG C, 80 DEG C and 85 DEG C.By N after pressure maintaining constant temperature 0.5-2h2Fast evacuation, preferably time be 0.5h,
1h, 1.5h and 2h, therefore overcritical N2The 2nd TPU plate obtained after infiltration is in solvent swelling state.
S40 foaming, as the 2nd TPU plate and CO2When gas homogenous system is reduced to rapidly normal pressure, nuclei of bubbles is in certain temperature
It rapidly grows up under the conditions of degree, these CO2It is extremely unstable, as the adjacent bubble of constantly growing up of bubble will merge, thus
Cause the rupture of walls and the reduction of bubble density.Density is big in order to obtain and ideal bubble structure that size is small, it is necessary to
The merging of strict control bubble.By the 2nd TPU plate be placed in 0.5-10min in 80-120 DEG C of thermostatic equipment foam to obtain hair
TPU sheet material after bubble.Blowing temperature be 80-120 DEG C in any temperature value, preferably 80 DEG C, 85 DEG C, 90 DEG C, 95 DEG C, 100 DEG C,
105 DEG C, 110 DEG C, 115 DEG C and 120 DEG C.Foamed time 0.5-10min, preferably 0.5min, 1min, 2 min, 3 min, 4
Min, 5 min, 6 min, 7 min, 8 min, 9 min and 10 min.Thermostatic equipment is water-bath, steam, hot wind and oil bath
One of equipment.
The TPU sheet drying is placed on pressure maintaining in closed high-pressure bottle and handled by S50 pressure maintaining.To the high pressure-volume
CO is passed through in device2And/or N2To the pressure of 1-5MPa, dwell time 15-26h.Because pressure used in pressure maintaining period compares
It is small, while 5MPa is usually less than in order to reduce high-pressure bottle pressure-bearing pressure-bearing used in device fabrication and maintenance cost.The gas being passed through
Body can individually select CO2, can also individually select N2, select other pressure holding effects of the two mixing preferable, the final products of acquisition
Performance it is more stable.CO2And N2Ratio be 0.5:1-2:1, preferably 1:1.Pressure is any pressure value in 1-5MPa, excellent
Select 1MPa, 2 MPa, 3 MPa, 4 MPa and 5MPa, dwell time preferred 15h, 16 h, 17 h, 18 h, 19 h, 20h, 20.5
H, 21 h, 21.5 h, 22 h, 23 h, for 24 hours, 25h and 26h.If the TPU sheet material obtained after foaming is not pressure maintaining processing, In
It will appear foam structure avalanche phenomenon after 6-8h, and the serious elasticity for reducing TPU sheet material.
S60 fretting map, by the TPU sheet material, fretting map is handled in thermostatic equipment.The fretting map step is will be described
TPU sheet material is put into 15-30s in 85-98 DEG C of thermostatic equipment, 40-50 DEG C of low temperature drying 30min.Thermostat temperature is in 85-98 DEG C
Any one temperature value, preferably 85 DEG C, 88 DEG C, 90 DEG C, 93 DEG C, 95 DEG C and 98 DEG C.Constant temperature time is appointing in 15-30s
What temperature value, preferably 15s, 18 s, 20 s, 22 s, 25 s, 28 s and 30 s.Drying temperature is appointing in 45-50 DEG C
What temperature value, preferably 45 DEG C, 48 DEG C and 50 DEG C.The preferred 30min of drying time.The fretting map step can be effectively
The appearance for preventing TPU sheet surface wrinkle keeps the TPU sheet surface finally obtained fuller.
Embodiment 1
The preparation of S10 sheet material, is heated to molten condition for the TPU raw material that hardness is 85A, is prepared into 4mm thickness by hot briquetting
TPU raw sheet;The TPU raw sheet, is cut into the first TPU plate of 15*7cm by S20 shearing;S30 infiltration, by the first TPU
Plate is placed in the autoclave of 5L and seals, and supercritical CO is passed through in autoclave2It is 15MPa to pressure, and is warming up to 60 DEG C,
By CO after pressure maintaining constant temperature 3h2Fast evacuation;Overcritical N is passed through in autoclave later2It is 5MPa to pressure, and is warming up to 50 DEG C,
By N after pressure maintaining constant temperature 1h2Fast evacuation;The first TPU plate after swelling is taken out into obtain the 2nd TPU plate out of autoclave
Material;The 2nd TPU plate is placed in the TPU sheet material after 3min in 95 DEG C of thermostatic equipment foams to foam by S40 foaming;S50
The TPU sheet drying is placed in closed high-pressure bottle, the CO of 0.5:1 is passed through in Xiang Suoshu high-pressure bottle by pressure maintaining2With
N2To the pressure of 1.8MPa, the dwell time is for 24 hours.How the TPU sheet material is put into 95 DEG C of thermostatic equipment by S60 fretting map
20s fretting map, and low temperature 30min dries TPU sheet material at 45 DEG C.
The size of TPU sheet material after final foaming obtained are as follows: 32*15*0.78cm;The property of TPU sheet material after foaming
It can be such as 1. embodiment 1TPU sheet properties data of following table.
1. embodiment 1TPU sheet properties of table:
Embodiment 2
The preparation of S10 sheet material, is heated to molten condition for the TPU raw material that hardness is 85A, is prepared into 1.8 thickness by hot briquetting
TPU raw sheet;The TPU raw sheet, is cut into the first TPU plate of 15*15cm by S20 shearing;S30 infiltration, by the first TPU
Plate is placed in the autoclave of 5L and seals, and supercritical CO is passed through in autoclave2It is 13MPa to pressure, and is warming up to 55 DEG C,
By CO after pressure maintaining constant temperature 1.5h2Fast evacuation;Overcritical N is passed through in autoclave later2It is 5MPa to pressure, and is warming up to 55
DEG C, by N after pressure maintaining constant temperature 1h2Fast evacuation;The first TPU plate after swelling is taken out into obtain the 2nd TPU out of autoclave
Plate;The 2nd TPU plate is placed in the TPU sheet material after 30s in 85 DEG C of thermostatic equipment foams to foam by S40 foaming;
The TPU sheet drying is placed in closed high-pressure bottle, the CO of 1:1 is passed through in Xiang Suoshu high-pressure bottle by S50 pressure maintaining2
And N2To the pressure of 1.2MPa, dwell time 20h.How S60 fretting map is put the TPU sheet material in 95 DEG C of thermostatic equipment
15s fretting map, and low temperature 30min dries TPU sheet material at 45 DEG C.
The size of TPU sheet material after final foaming obtained are as follows: 29*28*0.32cm;The property of TPU sheet material after foaming
It can be such as 2. embodiment 2TPU sheet properties data of following table.
2. embodiment 2TPU sheet properties of table:
Embodiment 3
The preparation of S10 sheet material, is heated to molten condition for the TPU raw material that hardness is 85A, is prepared into 3mm thickness by hot briquetting
TPU raw sheet;The TPU raw sheet, is cut into the first TPU plate of 15*7cm by S20 shearing;S30 infiltration, by the first TPU
Plate is placed in the autoclave of 5L and seals, and supercritical CO is passed through in autoclave2It is 15MPa to pressure, and is warming up to 55 DEG C,
By CO after pressure maintaining constant temperature 3h2Fast evacuation;Overcritical N is passed through in autoclave later2It is 5.5MPa to pressure, and is warming up to 55
DEG C, by N after pressure maintaining constant temperature 1h2Fast evacuation;The first TPU plate after swelling is taken out into obtain the 2nd TPU out of autoclave
Plate;The 2nd TPU plate is placed in the TPU after 2.5min in 90 DEG C of constant temperature water bath equipment foams to foam by S40 foaming
Sheet material;The TPU sheet drying is placed in closed high-pressure bottle, is passed through 0.8 in Xiang Suoshu high-pressure bottle by S50 pressure maintaining:
1 CO2And N2To the pressure of 1.6MPa, the dwell time is for 24 hours.How the TPU sheet material is put into 90 DEG C of constant temperature by S60 fretting map
20s fretting map in equipment, and low temperature 30min dries TPU sheet material at 50 DEG C.
The size of TPU sheet material after final foaming obtained are as follows: 31*14*0.58cm;The property of TPU sheet material after foaming
It can be such as 3. embodiment 3TPU sheet properties data of following table.
3. embodiment 3TPU sheet properties of table:
Embodiment 4
The preparation of S10 sheet material, is heated to molten condition for the TPU raw material that hardness is 85A, is prepared into 8mm thickness by hot briquetting
TPU raw sheet;The TPU raw sheet, is cut into the first TPU plate of 15*7ccm by S20 shearing;S30 infiltration, by the first TPU
Plate is placed in the autoclave of 5L and seals, and supercritical CO is passed through in autoclave2It is 18MPa to pressure, and is warming up to 80 DEG C,
By CO after pressure maintaining constant temperature 4h2Fast evacuation;Overcritical N is passed through in autoclave later2It is 7MPa to pressure, and is warming up to 80 DEG C,
By N after pressure maintaining constant temperature 1.5h2Fast evacuation;The first TPU plate after swelling is taken out into obtain the 2nd TPU plate out of autoclave
Material;The 2nd TPU plate is placed in the TPU sheet material after 5min in 98 DEG C of thermostatic equipment foams to foam by S40 foaming;S50
The TPU sheet drying is placed in closed high-pressure bottle, the CO of 1:1 is passed through in Xiang Suoshu high-pressure bottle by pressure maintaining2And N2
To the pressure of 2.3MPa, dwell time 26h.The TPU sheet material is put into 25s in 95 DEG C of constant temperature water bath equipment by S60 fretting map
Fretting map, and low temperature 30min dries TPU sheet material at 50 DEG C.
The size of TPU sheet material after final foaming obtained are as follows: 28*13*1.56cm;The property of TPU sheet material after foaming
It can be such as 4. embodiment 4TPU sheet properties data of following table.
4. embodiment 4TPU sheet properties of table:
Embodiment 5
The preparation of S10 sheet material, is heated to molten condition for the TPU raw material that hardness is 85A, is prepared into 1mm thickness by hot briquetting
TPU raw sheet;The TPU raw sheet, is cut into the first TPU plate of 15*15cm by S20 shearing;S30 infiltration, by the first TPU
Plate is placed in the autoclave of 5L and seals, and supercritical CO is passed through in autoclave2It is 12MPa to pressure, and is warming up to 50 DEG C,
By CO after pressure maintaining constant temperature 1.5h2Fast evacuation;Overcritical N is passed through in autoclave later2It is 5MPa to pressure, and is warming up to 50
DEG C, by N after pressure maintaining constant temperature 0.5h2Fast evacuation;By the first TPU plate after swelling taken out out of autoclave second
TPU plate;The 2nd TPU plate is placed in the TPU piece after 1min in 80 DEG C of thermostatic equipment foams to foam by S40 foaming
Material;The TPU sheet drying is placed in closed high-pressure bottle, is passed through 1:1's in Xiang Suoshu high-pressure bottle by S50 pressure maintaining
CO2And N2To the pressure of 1.2MPa, dwell time 15h.The TPU sheet material is put into 85 DEG C of thermostatic equipment by S60 fretting map
15s fretting map, and the TPU sheet material that low temperature 30min is dried at 45 DEG C.
The size of TPU sheet material after final foaming obtained are as follows: 31*30*0.18cm;The property of TPU sheet material after foaming
It can be such as 5. embodiment 5TPU sheet properties data of following table.
5. embodiment 5TPU sheet properties of table:
The dynamic compression shrinking percentage of TPU sheet material after the foaming is 0.72-0.78%, static compress shrinking percentage 19.2-19.6%.
The foregoing is merely exemplary embodiment of the present invention, are not intended to limit the invention patent protection scope, all
Using equivalent structure or equivalent flow shift made by description of the invention and accompanying drawing content, it is applied directly or indirectly in other
Relevant technical field, is included within the scope of the present invention.