INSULATION PRODUCT AND METHOD FOR MAKING INSULATION PRODUCT

Abstract

Disclosed is an insulation product comprising hemp fibres bonded together using one or more biopolymers. Hemp fibres having lengths of between 5 and 100 mm amount to at least 50% by weight of the product. A hemp containing insulating batt or board may be made from opened hemp fibres, opened biopolymer binder fibres, mixing to produce a mixture in which the components are dispersed, air-laying the mixture, heating to above the melting point of the biopolymer binder fibres, forming to a desired thickness or density; and cooling

Claims

1. A product comprising hemp fibres, bonded together using a biopolymer binder, wherein hemp fibres with lengths of between 5 and 100 mm amount to at least 50% by weight of the product.

2. A product as claimed in claim 1, wherein said biopolymer binder is biodegradable.

3. A product as claimed in claim 1,wherein said biopolymer binder has a melting point of below 180° C.

4. A product as claimed in claim 1,wherein the biopolymer binder is in the form of biopolymer fibres.

5. A product as claimed in claim 1, wherein the biopolymer binder comprises two or more biopolymers and/or biopolymer or biopolymers having two or more melting points.

6. A product as claimed in claim 5, wherein the biopolymer binder comprises biopolymer fibre having a core with a higher melting point than an outer sheath of each fibre.

7. A product as claimed in claim 1,wherein the product further comprises hemp shiv.

8. (canceled)

9. A product as claimed in claim 1, wherein hemp fibres with lengths of between 40 and 60 mm amount to at least 40% by weight of the product.

10. A product as claimed in claim 1, wherein the product contains plant or crop material other than hemp material and wherein the additional plant or crop material amounts to at least 10% by weight of the product.

11. A product as claimed in claim 10, wherein the additional plant or crop material comprises flax material, wherein the ratio of hemp material to flax material is in the range between 75:25 to 25:75.

12. A product as claimed in claim 1, wherein said hemp fibres amount to at least 70% by weight of the crop material or plant material used in the product.

13. A product as claimed in claim 1, in the form of an insulating batt, wherein hemp fibres of the lengths 30 to 70 mm amount to at least 95% by weight of the hemp material used in the product and which is bound by the biopolymer binder, wherein hemp fibres of the lengths 30 to 70 mm amount to at least 90% by weight of the material which is bound by the biopolymer binder, and wherein the product has a density of 10 kg/ m.sup.3 to 100 kg/ m.sup.3.

14. A product as claimed in claim 1, in the form of an insulating board, wherein hemp fibres of the lengths 30 to 70 mm amount to between 60% and 95% by weight of the hemp material used in the product and which is bound by the biopolymer binder, wherein hemp shiv amounts to at least 5% by weight, of the hemp material used in the product and which is bound by the biopolymer binder, and wherein the product has a density of 100 kg/ m.sup.3 to 200 kg/ m3.

15. A product as claimed in claim 1, wherein the biopolymer binder comprises one or more polyester or lignin-based biopolymers.

16. (canceled)

17. A method of making a product according to claim 1, comprising the steps of: Providing opened hemp fibres and biopolymer binder; Mixing the hemp fibres and biopolymer binder to produce a mixture in which the components are dispersed; Air-laying the mixture to form a layer; Heating the mixture to bind at least a proportion of the help fibres together with the biopolymer binder; Forming the layer to a desired thickness or density; and Cooling the layer or allowing it to cool.

18. (canceled)

19. The method of claim 17, comprising heating the biopolymer binder to soften or at least partially melt the biopolymer binder and thereby bind the hemp fibres.

20. A method as claimed in claim 17, wherein spiked cylinders are used to open and blend the said fibres.

21. (canceled)

22. A method as claimed in claim 17, in which the mixture is air-laid to form a layer in the form of a uniform slab.

23. A method as claimed in claim 22, further transporting said layer on a conveyor through a thermobonding oven.

24. (canceled)

25. Use of a product as claimed in claim 1 for insulation.

Description

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS

[0099] Non-limiting example embodiments will now be described.

Example 1

[0100] Thermal insulation batts were manufactured by the methods disclosed herein.

[0101] Polylactic acid (PLA) fibre binder (such as Ingeo™ Biopolymer 6302D ) and hemp fibres were each provided in the form of bales. Hemp crops had been cut, retted in the field, harvested into bales then separated into fibres and shives using a decortication mill to lengths of between 10-70 mm and then dust removed by mechanical filters before fibres were baled and shives packaged in bags. The relatively compressed fibre bales were fed into hoppers, dosed by weight and the fibres were then opened in mechanical opening machines and mixed to form a dispersed mixture within an airlay apparatus to achieve the desired density and product thickness prior to entering the oven

[0102] The mixture then exited the airlay apparatus as a matt layer, and was conveyed through an oven, with additional compression via a double belt system and heated to a temperature of between 120 - 160° C.] to partially melt or soften the biopolymer fibres and cause binding between the biopolymer fibres and the hemp fibres.

[0103] An optional step of forming is provided to produce insulating batts of required thickness or density. This forming step was conducted prior to and during cooling.

[0104] The resulting material was then cooled and its physical properties tested using standard industry methods.

Durability

[0105] Durability was tested by exposing the batts to high temperatures of up to 60° C. and high relative humidity, over 75%, in a climate chamber for 5 days.

[0106] No physical changes were observed following exposure to these conditions and the product’s thermal performance remained unchanged. The insulating batts were found to meet the requirements of British Standard BS 5250:2011+A1:2016 “Code of practice for control of condensation in buildings”.

Thermal Conductivity

[0107] Thermal conductivity was measured by the methods set out in ISO 9869 -1:2014, “Thermal insulation - Building elements - In-situ measurement of thermal resistance and thermal transmittance - Part 1: Heat flow meter method”.

[0108] Thermal conductivity of the insulating batts was found to be 0.038 W/mK. The insulating batts were found to meet the requirements of British Standard BS ISO 9869 - 1:2014.

Vapour Permeability

[0109] Vapour permeability was measured in accordance with the methods set out in ISO 12572:2001.

[0110] Vapour permeability of the insulating batts was found to be 2.Math.. The insulating batts were found to meet the requirements of British Standard BS 5250:2011+A1:201.

Density

[0111] Bulk density of the insulating batts was found to be 45 kg/m.sup.3.

Specific Heat Capacity

[0112] An estimate of the specific heat capacity was made by comparison of required electrical heat energy input required to raise the temperature of the insulating batts by a known amount above ambient temperature, to the heat input required to raise the temperature of a commercially available insulation product of known specific heat capacity.

[0113] Specific heat capacity was estimated to be 2100 J/(kg.K).

Example 2

[0114] Thermally and acoustically insulating boards were manufactured by the methods disclosed herein.

[0115] Polylactic acid (PLA) fibre binder (such as Ingeo™ Biopolymer 6302D ) and hemp fibres were each provided in the form of bales. Hemp crops had been cut, retted in the field, harvested into bales then separated into fibres and shives using a decortication mill to lengths of between 10-70 mm and then dust removed by mechanical filters before fibres were baled and shives packaged in bags. The relatively compressed fibre bales were fed into hoppers, dosed by weight and the fibres were then opened in mechanical opening machines and mixed to form a dispersed mixture within an airlay apparatus to achieve the desired density and product thickness prior to entering the oven.

[0116] In addition, hemp shives were added via a hopper at between 30-50% by weight of the total material weight

[0117] The mixture then exited the airlay apparatus as a matt layer, and conveyed through an oven, with significant additional compression via a double belt system and heated to a temperature of between 120 - 160° C. to partially melt or soften the biopolymer fibres and cause binding between the biopolymer fibres and the hemp fibres. The resulting material was then cooled.

[0118] Bulk density of the insulating boards was found to be 140 kg/m.sup.3.

[0119] Specific heat capacity was estimated to be 2100 J/(kg.K).

[0120] Acoustic Performance was estimated by comparison to commercially available products of known acoustic performance. The acoustic absorption coefficient α of the insulating boards was estimated to be 0.75.