Polyurethane Film and Bags - Properties and Characteristics

Polyurethane Properties and Characteristics

Thermoplastic polyurethanes (TPU) combines the best of rubber and plastic, without the weaknesses inherent in plasticized vinyl films that are subject to brittleness and other problems caused when plasticizers leach to the surface. Urethane is easy to work with, and is readily modified to suit a particular application through the addition of fillers, colors, stabilizers, and lubricants, as well as other additives.

Durometer (Hardness) Urethane film and sheet can be produced in a range of durometers (Shore A 75 - Shore D 55) from relatively stiff to a thin film having an extremely soft, non-plastic feel that is ideal for products that come in contact with the skin.
Low temperature flexibility Urethanes feature superior flexibility over a wide durometer range, even at temperatures as low as -60°F (-50°C).
Tensile strength Tensile strength ranges from 4,000 to 10,000 psi, assuring reliability and durability over the life span of the end product. Because urethanes are tough, they can be used in thinner gauges when compared to vinyl.
Elongation TPU film and sheet can elongate as much as 800% and return to its original dimension without significant loss of "memory."
Abrasion resistance Polyurethane provides excellent abrasion resistance. In profile form it is tough enough for conveyor drive belts and protective sheaves for elevator cables and pulleys.
Chemical and environmental resistance Polyether and polyester urethanes each have specific chemical resistance characteristics, such as resistance to hydrocarbons, chemicals, ozone, bacteria, fungus, and moisture, as well as skin oils. They provide durability and long life in harsh industrial environments.
Fabrication versatility Urethane can be fabricated in many ways with many different substrates, enhancing design versatility. Sheet can be fabricated with urethane tubing to provide the benefits of urethane to an entire product system, such as in linked bladder applications.

Our Urethane can be:

Cut
Sewn
Adhesive bonded
Laminated
Vacuum formed
Radio frequency (RF) sealed
Thermally bonded to itself or other materials
Printed or silk-screened

Film and Sheet

TPU offers a broad range of high-performance properties and characteristics, making it the material of choice for many "can't fail" applications. It is inherently strong, tough, and easy to work with, and unlike vinyl, it contains no plasticizers, so it won't become brittle or lose its performance properties over time.

TPU compounds possess a combination of properties not available in any other thermoplastic material. When two of these properties are needed in an application, such as low temperature flexibility and soft durometer, TPU will usually outperform any other material. (View properties comparison chart)

Our Urethane offers a full range of thermoplastic polyurethane, including aromatic and aliphatic materials in both polyester and polyether. Film and sheet are available in thicknesses from .001" to .060", and in widths from 6" to 96". Our films are available in Tubular form, single wound sheeting and other configurations. A variety of colors, opacities and surface textures are available.

Standard grades of Urethane film and sheet satisfy most application requirements. Other grades are available or can be custom compounded to meet specific application needs, including films rated for potable water contact and UL Listed flame-resistance, as well as food and medical requirements.

Properties of The Film - TPU

Tear strength

Tear strength is the term which defines the resistance of a notched test specimen ( TPU Elastomers ) to tear propagation. Tear strength is generally regarded as the critical indication of the physical strength to external force. In this respect, our film is superior to most of other plastics.

Properties	The Film		PVC		NBR	CR	NR
Hardness shore A	96	90	94	87	78	70	77
Tear Strength (kN/m)
Right angle cut	129	80	70	70	37	36	65
Line cut	137	63	38	48	19	25	40

Abrasion resistance

Our film can withstand a lot of physical abuse including scratch, friction, corrosion forced upon the surface of the materials. With over three times the durability of rubber, Our film provides excellent abrasion resistance, functioning well across a broad range of end-applications.

The Film	Rubber		Nylon		PVC		PE		Other Plastic
Abrasion (mg)	Item	Abression (mg)	Item	Abression (mg)	Item	Abression (mg)	Item	Abression (mg)	Item	Abression (mg)
0.5 ~ 3.5	SBR	177	NYLON6	366	General	160	HDPE	29	PS	324
	NBR	205	NYLON66	49	Soft grade	187	LDPE	70	PBS	545
	CR	280	NYLON610	16	Hi-strength	122			PET	18
	NR	146	NYLON11	24					ABS	275

Flex-Crack resistance

Flex-crack resistance should be taken into account when it comes to the selection of composite film that are constantly under severe external force, and the stability to flex is critical. Our film exhibits excellent dynamic flex performance and has lead to the use in many demanding applications.

Properties	The Film		PVC		NBR	CR	NR
Hardness shore A	96	90	94	87	78	70	77
Flexural (10K Time)	192	300 *	165	300 **	10	300 **	25
no crack effect after 3000K times *Crack effect becomes inevitable after 3000K times

Hydrolysis resistance

At normal temperatures, our film exhibits outstanding resistance to hydrolysis for 1-2 years without undergoing any changes (decomposition) while its mechanical properties are still maintained. In particular, our film Ether grade demonstrates superior hydrolysis resistance to Ester grade. If Polyester based TPU film series is exposed for six months to hot water at 50 degrees ( or at 70 degrees for three weeks, or 100 degrees for 3 to 4 days ), an irreversible break down of the Polyester chains will occur through hydrolysis ( decomposed ) ; and as the consequences, the mechanical properties of the film will deteriorate. In this respect, our film is regarded as environmentally friendly materials. For end applications that constant contact with water is inevitable, our film Ether grade is certainly the ideal candidate to be taken into consideration.

Resistance to oil, chemicals and greases

The excellent resistance to greases and pure mineral oils (such as lubricating, fuel, and diesel oils) provided by our film makes it well suited for many industrial and food contact applications. Our film does not react chemically to the oil contamination and usually results in higher tensile strength than the initial properties detected. While the response of other plastics materials to oil contamination appears to be poor, Our film has once again proved to be superior to other plastics materials. However, in the case of contamination of water identified in mineral oils, the reduction in TPU film physical properties is inevitable.

Properties

ASTM No.1 oil

ASTM No.3 oil

The Film

NBR

The Film

NBR

Hardness

Tensile strength

Elongation

Volume

+5.5

+15.5

-0.5

+15

+20.1

-21.5

-3.8

-2

-10.2

-13.2

+1.5

-1

-6.5

-6.8

+3.7

-6

-5.6

-17.6

-12.7

-20

-27.3

-33.3

+56.2

Heat resistance and ageing (Weatherability)

Plastics are chemically degraded by the effect of UV-radiation and heat. For outdoor applications, weather stability is an important criteria in material selection. For use in high temperature ( above 70 degrees, for example ), various grades are available that can provide additional protection against degradation ( oxidized, aging) under any severe climates. Our film can be used over a wide range of temperatures. While Ester grade can withstand temperatures up to 130 degrees, Ether grade can withstand up to 90 degrees. The table below shows the comparison of our film to other plastics to other plastics in respect to degradation.

Properties	The Film Ester base		PVC		NBR	CR	NR
Properties	95A	85A	85 PHR	80 PHR	NBR	CR	NR
Tensile /MPa first	34.3	25.3	16.0	16.3	11.6	10.3	16.3
after aged**	51.3	42.4	14.6	18.1	9.8	9.6	5.6
variation	150	168	91	111	85	93	34
Elongation first	700	517	308	350	400	400	450
after aged ?	460	600	213	238	188	238	450
variation	66	116	69	68	47	60	0

Low Temperature Flexibility

Our film can withstand temperature down to -30 degrees while mechanical and physical properties are still maintained. Most importantly, our film will not become brittle and can thus be utilized as a replacement for PVC. In this respect, our film can be used for applications that require superior low temperature flexibility.

Microbiological resistance

Polyether-based thermoplastic Polyurethane exhibits excellent resistance to microbiological attack. The table below shows some comparative results of microbial degradation from various elastomers materials.

Microbe

The Film
Ether base

PVC

NBR

95A

85A

Mildew (1)

Mildew (1)

Other Microbe

>30

>60

>30

>60

>30

>60

<10

>10

<10

Gas permeability

Our film can be easily processed by high frequency or hot plate welding and has been widely used in inflatable end-applications. The diffusion coefficient is a material constant which specifies the volume of gas that will pass through a test specimen of known surface area and thickness in a fixed time, with a given partial pressure difference. The diffusion coefficient varies to certain extent depending on the type of gas in questions. Generally speaking, our filmEster series has superior gas permeability to Ether grade.

Biocompatibility

Our film exhibits superior biocompatibility. With the characteristics of sterilization, anti- allergic, without creating the source of heat and agitation to parts, Our filmare widely utilized in medical, sanitary, sport, or protective devices.