Coated non-woven fibrous mat

Abstract

The present invention provides to a coated non-woven fibrous mat, the coated non-woven fibrous mat comprising: (a) a precursor mat comprising: a non-woven web of fibers comprising glass fibers, and a first binder; and (b) a coating which coats the precursor mat, wherein the coating comprises a second binder, wherein the second binder is a polyvinyl alcohol binder with a weight average molecular weight in the range of about 100000 g / mole to about 500000 g / mol; and wherein: the coated non-woven fibrous mat has an air permeability of ≤ about 70 L / m2 / s as measured according to ASTM D737. The invention also provides methods for manufacturing the coated non-woven fibrous mat, and a construction board comprising the coated non-woven fibrous mat.

Description

[0001] Coated Non-Woven Fibrous Mat

[0002] The present invention relates to a coated non-woven fibrous mat, methods for manufacturing a coated non-woven fibrous mat, and a construction board comprising the coated non-woven fibrous mat.

[0003] Background

[0004] Glass veils (also known as mats, non-wovens, or webs) are manufactured for various applications such as facers for polyisocyanurate insulation boards used for external thermal insulation composite systems (ETICs).

[0005] The glass veils are currently impregnated with poly- or per-fluoroalkyl substances (PFAS). The PFAS- impregnated glass veils prevent bleed-through of polyisocyanurate foam during the manufacture of the insulation boards. The glass veil contains the expanding polyisocyanurate foam (made from a mixture of isocyanate and polyol) without going through the glass veil because it would soil the conveyor of the production line.

[0006] The PFAS-impregnated glass veils typically are porous. Despite their open structure, they have highly repellent properties to the foam due to the hydrophobic and oleophobic qualities introduced to the glass veil by the PFAS.

[0007] However, PFAS will be banned under European legislation in the near future, and as a result, more sustainable PFAS-free glass veils have been developed. These include a heavy, mineral-coated glass non-woven. The coated glass facers have a very low porosity and work as facers in the polyisocyanurate process because the surface is physically closed due to the thick mineral coating. The thick coating on top of the glass nonwoven makes it a vulnerable design for especially the ETICS application. The ETICS render applied to the mineral coating of the coated glass facer does not adhere well and gives a significantly higher risk in long term weathering and durability performance.

[0008] It is an object of the present invention to overcome or mitigate at some of the problems of the prior art.

[0009] In particular, it is an object of the invention to provide a coated glass non-woven which has two significant benefits in that it (a) is lightweight, and (b) has an unexpectedly low air permeability (measured with Textest instrument) which makes it suitable for use as a facer in the polyisocyanurate process.

[0010] Definitions

[0011] The point of attachment of a repeat unit, moiety, or substituent is represented by For example, - COOH is attached through the carbon atom. The term “about” or “approximately” means an acceptable error for a particular value as determined by a person of ordinary skill in the art, which depends in part on how the value is measured or determined. The term “about” or “approximately” may mean within 1 , 2, 3 or 4 standard deviations. The term “about” or “approximately” may mean within 30%, 25%, 20%, 15%, 10%, 9%, 8%, 7%, 6%, 5%, 4%, 3%, 2%, 1 %, or 0.5% of a given value or range.

[0012] Unless otherwise specified, “a,” “an,” “the,” and “at least one” are used interchangeably. Furthermore, as used in the description of the application and the appended claims, the singular forms “a,” “an,” and “the” are inclusive of their plural forms, unless contradicted by the context surrounding such.

[0013] “Alkyl” refers to a straight-chain, branched, or cyclic saturated hydrocarbon group. The alkyl group may have from 5-20 carbon atoms, for example from 7-17 carbon atoms, such as 10-15 carbon atoms. The alkyl group may be unsubstituted. Alternatively, the alkyl group may be substituted. Unless otherwise specified, the alkyl group may be attached at any suitable carbon atom and, if substituted, may be substituted at any suitable atom.

[0014] “Aryl” refers to an aromatic carbocylic group or aromatic heterocarbocyclic group. When the aryl group is an aromatic carbocylic group, the aryl group may have a single ring or multiple condensed rings. The aryl group can have from 5-20 carbon atoms, for example from 6-20 carbon atoms, such as 6-12 carbon atoms. The aryl group may be unsubstituted. Alternatively, the aryl group may be substituted. Unless otherwise specified, the aryl group may be attached to any suitable carbon atom and, if substituted, may be substituted at any suitable atom. Examples of aryl groups include, but are not limited to, phenyl, tolyl (o-, m-, or p-), naphthyl, anthracenyl, and the like.

[0015] When the aryl group is an aromatic heterocarbocyclic group, one or more (e.g. 1 , 2, 3, or more) of the carbon atoms in an aromatic carbocylic group is independently substituted with a heteroatom provided aromaticity is maintained. An aromatic heterocarbocyclic group may also be known as a heteroaryl group. The heteroaryl group may have a single ring or multiple condensed rings. The or each heteroatom may be independently selected from the group consisting of nitrogen, oxygen, phosphorus, sulfur. The or each heteroatom may be selected from nitrogen. The heteroaryl group may have from 4-20 carbon atoms, for example from 5-20 carbon atoms, such as from 5-15 carbon atoms. The heteroaryl group may be unsubstituted. Alternatively, the heteroaryl group may substituted. Unless otherwise specified, the heteroaryl group may be attached at any suitable atom and, if substituted, may be substituted at any suitable atom. Examples of heteroaryl groups include but are not limited to thienyl, furanyl, pyrrolyl, imidazolyl, pyrazolyl, thiazolyl, isothiazolyl, oxazolyl, isoxazolyl, triazolyl, thiadiazolyl, thiophenyl, oxadiazolyl, pyridinyl, pyrimidyl, benzoxazolyl, benzthiazolyl, benzimidazolyl, indolyl, quinolinyl, and the like.

[0016] The term “consisting” is closed and excludes additional, unrecited elements or method steps in the claimed invention. The term “consisting essentially of’ is semi-closed and occupies a middle ground between “consisting” and “comprising”. “Consisting essentially of’ does not exclude additional, unrecited elements or method steps which do not materially affect the essential characteristic(s) of the claimed invention.

[0017] The term “comprising” is inclusive or open-ended and does not exclude additional, unrecited elements or method steps in the claimed invention. The term is synonymous with “including but not limited to”. The term “comprising” encompasses three alternatives, namely (i) “comprising”, (ii) “consisting”, and (iii) “consisting essentially of’.

[0018] The terms “mat”, “veil”, and “facer” are used interchangeably herein and refer to a bound web of fibers.

[0019] The term “poly- or per-fluoroalkyl substances” or “PFAS” refers to synthetic organofluorine compounds having one or more poly- or per-fluoroalkyl functional group.

[0020] The term “room temperature” is about 20 °C.

[0021] Viscosity is a function of the rate of shear. A decrease in the viscosity of a composition with increasing rate of shear is called “shear thinning”, and an increase in the viscosity of a composition is called “shear thickening”.

[0022] The term “substantially free” means that the selected composition contains less than a functional amount of the stated ingredient or component, typically less than about 0.1 wt%, such as less than about 0.05 wt%, for example, less than about 0.03 wt% of the total composition.

[0023] “Substituted” refers to a group in which one or more (e.g. 1 , 2, 3, 4, or 5) hydrogen atoms are each independently replaced with substituents which may be the same or different. The substituent may be any group which does not adversely affect the aqueous composition of the invention, the coating of the coated non-woven mat of the invention, the coated non-woven mat of the invention, or the precursor mat. Examples of substituents include, but are not limited to, -Ra, -O-Ra, -NRaRb, -CN, -COORa, and -CONRaRb, preferably -Ra. Raand Rbare independently selected from the groups consisting of H, alkyl, and aryl, such as phenyl, tolyl (o-, m-, or p-), naphthyl, anthracenyl, methyl, ethyl, n-propyl, i- propyl, n-butyl, i-butyl, t-butyl, pentyl, cyclo-pentyl, hexyl, cyclo-hexyl and the like.

[0024] Brief Description of the Figures

[0025] Certain aspects of the embodiments described herein may be more clearly understood by reference to the drawing, which is intended to illustrate but not limit, the invention, and wherein:

[0026] Figure 1 shows a representative photograph of a coated non-woven fibrous mat coated with a 10 wt% solution of Mowiol® 28-99 (sold by Kuraray) using an RK laboratory multicoater. Description of the Invention

[0027] Coated Non-Woven Fibrous Mat

[0028] In one aspect, the present invention provides to a coated non-woven fibrous mat, the coated non-woven fibrous mat comprising:

[0029] (a) a precursor mat comprising:

[0030] • a non-woven web of fibers comprising glass fibers, and

[0031] • a first binder; and

[0032] (b) a coating which coats the precursor mat, wherein the coating comprises a second binder, wherein the second binder is a polyvinyl alcohol binder with a weight average molecular weight in the range of about 100000 g / mole to about 500000 g / mol; wherein: the coated non-woven fibrous mat has an air permeability of < about 70 L / m2 / s as measured according to ASTM D737.

[0033] The coated non-woven fibrous mat comprises a precursor mat. The precursor mat has a first major surface and a second major surface opposite to the first major surface. The coating may be applied to the first or second major surfaces.

[0034] The coating may not comprise poly- or per-fluoroalkyl substances (PFAS) i.e. the coating is PFAS-free. In this respect, PFAS are not purposefully added to the coating to increase the water repellent property of the coating. The coating, however, may be prepared from e.g. tap water, which may contain PFAS as an impurity or residue. A PFAS-free coating therefore may comprise trace quantities of PFAS introduced as an impurity or residue.

[0035] The coating comprises a second binder. The second binder is a polyvinyl alcohol (PVOH) binder with a weight average molecular weight in the range of about 100000 g / mole to about 500000 g / mol. Specific polyvinyl alcohol binders chosen according to the invention produce a lightweight and low air permeability mat, which makes the mat suitable for use as a facer for construction boards, in particular polyisocyanurate foam boards. In addition, the performance of the resulting board is good in terms of stability towards humidity and moisture. As the coated non-woven fibrous mats may be used in polyisocyanurate foam boards in external thermal insulation composite systems, the foam boards will be exposed to rain, snow, and humidity before a render is applied on top of it. It is of benefit therefore for the coated non-woven fibrous mat to exhibit sufficient resistance to these weather conditions.

[0036] The binder is a polyvinyl alcohol binder with a weight average molecular weight (Mw) in the range of about 100000 g / mole to about 500000 g / mol. The weight average molecular weight of the polyvinyl alcohol binder may be > about 100000 g / mol.

[0037] The weight average molecular weight of the polyvinyl alcohol binder may be > about 105000 g / mol. The weight average molecular weight of the polyvinyl alcohol binder may be > about 110000 g / mol. The weight average molecular weight of the polyvinyl alcohol binder may be > about 115000 g / mol. The weight average molecular weight of the polyvinyl alcohol binder may be > about 120000 g / mol. The weight average molecular weight of the polyvinyl alcohol binder may be > about 125000 g / mol. The weight average molecular weight of the polyvinyl alcohol binder may be > about 130000 g / mol. The weight average molecular weight of the polyvinyl alcohol binder may be > about 135000 g / mol.

[0038] The weight average molecular weight of the polyvinyl alcohol binder may be < about 500000 g / mol.

[0039] The weight average molecular weight of the polyvinyl alcohol binder may be < about 450000 g / mol.

[0040] The weight average molecular weight of the polyvinyl alcohol binder may be < about 400000 g / mol.

[0041] The weight average molecular weight of the polyvinyl alcohol binder may be < about 350000 g / mol.

[0042] The weight average molecular weight of the polyvinyl alcohol binder may be < about 300000 g / mol.

[0043] The weight average molecular weight of the polyvinyl alcohol binder may be < about 250000 g / mol.

[0044] The weight average molecular weight of the polyvinyl alcohol binder may be > about 110000 g / mol to < about 300000 g / mol. The weight average molecular weight of the polyvinyl alcohol binder may be > about 120000 g / mol to < about 250000 g / mol. The weight average molecular weight of the polyvinyl alcohol binder may be > about 140000 g / mol to < about 250000 g / mol.

[0045] The weight average molecular weight of the polyvinyl alcohol binder may be > about 140000 g / mol to < about 150000 g / mol.

[0046] The weight average molecular weight of the polyvinyl alcohol binder may be > about 190000 g / mol to < about 200000 g / mol.

[0047] The weight average molecular weight of the polyvinyl alcohol binder may be > about 165000 g / mol to < about 180000 g / mol.

[0048] The weight average molecular weight of the polyvinyl alcohol binder may be measured by gel permeation chromatography.

[0049] The polyvinyl alcohols (PVOH) are commercially available, and may be produced by hydrolysing polyvinyl acetate (PVA). The amount of hydroxylation determines its physical and mechanical properties. The dry polymer is a hard, colorless, and odorless crystalline thermoplastic with a Tg of about 375 K (about 102 °C). It is highly water soluble, fully biodegradable but resistant to organic solvents and oils, with high tensile strength, and elasticity. Polyvinyl acetate may be hydrolysed to a high degree (e.g. greater than 85 mol%). In this instance, the resulting polyvinyl alcohols become more difficult to solubilize and films on drying become more resistant to humidity and rain because of an increasing level of hydrogen bonding occurring between intra- and intermolecular hydroxyl groups.

[0050] The degree of hydrolysis of the polyvinyl alcohol may be > about 85 mol%. The degree of hydrolysis of the polyvinyl alcohol may be > about 88 mol%. The degree of hydrolysis of the polyvinyl alcohol may be > about 90 mol%. The degree of hydrolysis of the polyvinyl alcohol may be > about 92 mol%. The degree of hydrolysis of the polyvinyl alcohol may be > about 94 mol%. The degree of hydrolysis of the polyvinyl alcohol may be > about 95 mol%. The degree of hydrolysis of the polyvinyl alcohol may be > about 96 mol%. The degree of hydrolysis of the polyvinyl alcohol may be > about 97 mol%. The degree of hydrolysis of the polyvinyl alcohol may be > about 98 mol%.

[0051] The degree of hydrolysis of the polyvinyl alcohol may be > about 95 mol% and < about 99.9 mol%, such as > about 95 mol% and < about 98 mol%.

[0052] The degree of hydrolysis of the polyvinyl alcohol may be > about 98 mol% and < about 99.9 mol%.

[0053] The degree of hydrolysis can be measured by titration with a base, typically a strong base. This method is well known from the skilled in the art for measuring saponification index.

[0054] The polyvinyl alcohol may have a viscosity measured at 4 wt% in water at room temperature with a Brookfield synchronized-motor rotary viscometer that is > about 25 mPa.s. It may be > about 28 mPa.s.

[0055] A Brookfield synchronized-motor rotary viscometer is a standard piece of equipment to the person skilled in the art. The skilled person is used to handling the viscometer and knows how to adjust its operating conditions to obtain a precise measurement. To obtain a precise measurement, one important parameter, well known by the person skilled in the art, is to operate with a Torque ranging from 40 to 80% to ensure a standard deviation of less than 2%. Outside of this range, the deviation is higher, and the result is not precise.

[0056] The spindle and the rotary speed can vary from one Brookfield synchronized-motor rotary viscometer to another. The skilled person knows that the spindle and rotary speed can be adjusted to find the right combination that allows the Torque range target to be met. The polyvinyl alcohol may have a viscosity measured at 4 wt% in water at room temperature with a Brookfield synchronized-motor rotary viscometer that is < about 98 mPa.s. It may be < about 70 mPa.s, preferably < about 60 mPa.s.

[0057] The polyvinyl alcohol may have a viscosity measured at 4 wt% of said polyvinyl alcohol in water at room temperature with a Brookfield synchronized-motor rotary viscometer of > about 25 mPa.s and < about 98 mPa.s.

[0058] The polyvinyl alcohol may have a viscosity measured at 4 wt% of said polyvinyl alcohol in water at room temperature with a Brookfield synchronized-motor rotary viscometer of > about 25 mPa.s and < about 60 mPa.s.

[0059] Suitable polyvinyl alcohol binders include, but are not limited to, Mowiol® 28-99, Poval™ 56-98, and Mowiol® 95-88 which are commercially available from Kuraray. The first number in the Mowiol® or Poval™ designation (e.g. 28, 56 or 95) indicates the viscosity of the polyvinyl alcohol measured with a 4 wt% aqueous solution at room temperature (about 20°C) with a Brookfield synchronized-motor rotary viscometer. The second number in the Mowiol® or Poval™ designation (e.g. 88, 98 or 99) indicates the degree of hydrolysis of the PVOH. For example, Mowiol® 28-99 has a viscosity of about 28 mPa.s when measured with a 4% aqueous solution at room temperature (about 20°C) with a Brookfield synchronized-motor rotary viscometer, and a degree of hydrolysis of about 99 mol%.

[0060] The polyvinyl alcohol binder binder may have a viscosity of about 28 mPa.s to about 40 mPa.s when measured with a 4% aqueous solution at room temperature (about 20°C) with a Brookfield synchronized-motor rotary viscometer, and a degree of hydrolysis of about 99 mol%.

[0061] The polyvinyl alcohol binder binder may have a viscosity of about 56 mPa.s to about 58 mPa.s when measured with a 4% aqueous solution at room temperature (about 20°C) with a Brookfield synchronized-motor rotary viscometer, and a degree of hydrolysis of about 98 mol%.

[0062] The polyvinyl alcohol binder binder may have a viscosity of about 95 mPa.s to about 98 mPa.s when measured with a 4% aqueous solution at room temperature (about 20°C) with a Brookfield synchronized-motor rotary viscometer, and a degree of hydrolysis of about 88 mol%.

[0063] The coated non-woven fibrous mat is asymmetric. By “asymmetric”, we mean that the aqueous composition of the present invention does not completely penetrate through the entire thickness of the precursor mat. Instead, the aqueous composition coats or sits solely on one side of the precursor mat after application i.e. on one major surface of the precursor mat. In this respect, the aqueous composition will be detectable on the coated side of the precursor mat but will not be detectable on the other (uncoated) side of the mat. Likewise, the coating (i.e. the aqueous composition after being dried) will be detectable on the coated side of the precursor mat but will not be detectable on the other (uncoated) side of the mat.

[0064] The coating may partially penetrate the precursor mat uniformly or substantially uniformly. In this respect, the coating may partially extend into the thickness of the precursor mat to a uniform degree along the length and width of the precursor mat. Alternatively, the coating may partially extend into the thickness of the precursor mat to a substantially uniform degree along the length and width of the precursor mat.

[0065] The coating may penetrate the precursor mat between > about 0.1 % to < about 50% of the thickness of the precursor mat. The thickness of the precursor mat and / or coated non-woven fibrous mat may be measured in accordance with ASTM D1777.

[0066] The coating may penetrate the precursor mat > about 0.1 % of the thickness of the precursor mat. The coating may penetrate the precursor mat > about 0.2% of the thickness of the precursor mat. The coating may penetrate the precursor mat > about 0.3% of the thickness of the precursor mat. The coating may penetrate the precursor mat > about 0.4% of the thickness of the precursor mat. The coating may penetrate the precursor mat > about 0.5% of the thickness of the precursor mat.

[0067] The coating may penetrate the precursor mat < about 45% of the thickness of the precursor mat. The coating may penetrate the precursor mat < about 40% of the thickness of the precursor mat. The coating may penetrate the precursor mat < about 35% of the thickness of the precursor mat. The coating may penetrate the precursor mat < about 30% of the thickness of the precursor mat. The coating may penetrate the precursor mat < about 25% of the thickness of the precursor mat. The coating may penetrate the precursor mat < about 20% of the thickness of the precursor mat. The coating may penetrate the precursor mat < about 15% of the thickness of the precursor mat. The coating may penetrate the precursor mat < about 10% of the thickness of the precursor mat.

[0068] The coating may penetrate the precursor mat between > about 0.5% to < about 30% of the thickness of the precursor mat, such as about > about 0.5% to < about 20% of the thickness of the precursor mat, for example > about 0.5% to < about 10% of the thickness of the precursor mat.

[0069] The precursor mat comprises (a) a non-woven web of fibers comprising glass fibers and optionally polyester fibers, and (b) a first binder, or combination thereof.

[0070] A non-woven web of fibers means that the fibers are randomly orientated.

[0071] The precursor mat may not comprise poly- or per-fluoroalkyl substances (PFAS) i.e. the precursor mat is PFAS-free. In this respect, PFAS are not purposefully added to the precursor mat to increase the water repellent property of the precursor mat. The precursor mat, however, may be prepared using e.g. tap water, which may contain PFAS as an impurity or residue. A PFAS-free precursor mat therefore may comprise trace quantities of PFAS introduced as an impurity or residue.

[0072] The precursor mat may comprise a non-woven web of fibers comprising glass fibers i.e. the precursor mat does not contain polyester fibers. Alternatively, the precursor mat may comprise a non-woven web of fibers comprising glass fibers and polyester fibers.

[0073] The glass fibers may comprise one or more (e.g. 2, 3, 4, or 5) groups of glass fibers. The glass fibers may comprise a single group of fibers. The glass fibers may comprise more than one (e.g. two or more, optionally two) groups of glass fibers.

[0074] When the glass fibers comprise two or more groups of glass fibers, the glass fibers may be (a) manufactured from the same type of glass but have differing dimensions (average diameter and / or average length), (b) manufactured from different types of glass but have the same or similar dimensions within manufacturing tolerances, or (c) manufactured from different types of glass and having differing dimensions (average diameter and / or average length).

[0075] When the precursor mat comprises two or more (e.g. two or three) groups of glass fibers, the precursor mat may also comprise polyester fibers. Alternatively, the precursor mat may comprise two or more (e.g. two or three) groups of glass fibers and no polyester fibers.

[0076] The glass fibers may be formed by conventional methods known to those skilled in the art. In this respect, the glass fibers may be formed by a continuous manufacturing process in which molten glass passes through the holes of a bushing, the streams of molten glass thereby formed are solidified into filaments, and the filaments are combined together to form a fiber, “roving,” “strand,” or the like.

[0077] After the glass fibers are drawn from the bushing, an aqueous sizing composition (also referred to as a size) may optionally be applied to the fibers. The sizing composition is not limited, and may be any sizing composition known to those of skill in the art. Generally sizing compositions contain a lubricant to protect the fibers from damage by abrasion. The sizing composition may be applied by conventional methods such as by an application roller or by spraying the size directly onto the fibers. The size protects the glass fibers from breakage during subsequent processing, helps to retard interfilament abrasion, ensures the integrity of the strands of glass fibers, promotes the interconnection of the glass filaments that form the strand, etc.

[0078] After the glass fibers are treated with the sizing composition, they may be chopped for subsequent processing into a wet-laid, non-woven mat as described below.

[0079] The glass fibers may have a mean fiber diameter as described below and a mean fiber length as described below. The glass fibers may have a mean fiber diameter in the range of > about 5 pm and < about 20 pm. The glass fibers may have a mean fiber diameter in the range of > about 6 pm and < about 17 pm. The glass fibers may have a mean fiber diameter in the range of > about 7 pm and < about 15 pm.

[0080] The glass fibers may have a mean fiber diameter of > about 6 pm. The glass fibers may have a mean fiber diameter of > about 6.5 pm. The glass fibers may have a mean fiber diameter of > about 7 pm. The glass fibers may have a mean fiber diameter of > about 8.5 pm. The glass fibers may have a mean fiber diameter of > about 9 pm. The glass fibers may have a mean fiber diameter of > about 9.5 pm.

[0081] The glass fibers may have a mean fiber diameter of < about 17 pm. The glass fibers may have a mean fiber diameter < about 16.5 pm. The glass fibers may have a mean fiber diameter of < about 16 pm. The glass fibers may have a mean fiber diameter of < about 15.5 pm. The glass fibers may have a mean fiber diameter of < about 15 pm. The glass fibers may have a mean fiber diameter of < about 14.5 pm. The glass fibers may have a mean fiber diameter of < about 14 pm. The glass fibers may have a mean fiber diameter of < about 13.5 pm. The glass fibers may have a mean fiber diameter of < about 13 pm. The glass fibers may have a mean fiber diameter of < about 12.5 pm. The glass fibers may have a mean fiber diameter of < about 12 pm. The glass fibers may have a mean fiber diameter of < about 11 .5 pm. The glass fibers may have a mean fiber diameter of < about 11 pm. The glass fibers may have a mean fiber diameter of < about 10.5 pm.

[0082] The glass fibers may have a mean fiber diameter of about 10 pm.

[0083] The glass fibers may have a mean fiber length in the range of > about 1 mm and < about 20 mm. The glass fibers may have a mean fiber length in the range of > about 2 mm and < about 15 mm. The glass fibers may have a mean fiber length in the range of > about 3 mm and < about 10 mm.

[0084] The glass fibers may have a mean fiber length of > about 3 mm. The glass fibers may have a mean fiber length of > about 3.5 mm. The glass fibers may have a mean fiber length of > about 4 mm. The glass fibers may have a mean fiber length of > about 4.5 mm. The glass fibers may have a mean fiber length of > about 5 mm. The glass fibers may have a mean fiber length of > about 5.5 mm.

[0085] The glass fibers may have a mean fiber length < about 10 mm. The glass fibers may have a mean fiber length of < about 9.5 mm. The glass fibers may have a mean fiber length of < about 9 mm. The glass fibers may have a mean fiber length of < about 8.5 mm. The glass fibers may have a mean fiber length of < about 8 mm. The glass fibers may have a mean fiber length of < about 7.5 mm. The glass fibers may have a mean fiber length of < about 7 mm. The glass fibers may have a mean fiber length of < about 6.5 mm.

[0086] The glass fibers may have a mean fiber length of about 6 mm. The glass fibers may further comprise glass fibers having a smaller average diameter than those described above. The glass fibers therefore may be a mixture or blend of two groups of fibers, in which one group of fibers has a larger average diameter than the other group of fibers.

[0087] If present, the second group of glass fibers may have a mean fiber diameter < about 5 pm. The second group of glass fibers may have a mean fiber diameter in the range of > about 1 pm and < about 5 pm, such as about > about 1 pm and < about 4.5 pm, for example, about > about 1 .5 pm and < about 4 pm.

[0088] The second group of glass fibers may have a mean fiber length in the range of > about 1 mm and < about 20 mm. The second group of glass fibers may have a mean fiber length in the range of > about 2 mm and < about 15 mm. The second group of glass fibers may have a mean fiber length in the range of > about 3 mm and < about 10 mm.

[0089] The second group of glass fibers may have a mean fiber length of > about 3 mm. The second group of glass fibers may have a mean fiber length of > about 3.5 mm. The second group of glass fibers may have a mean fiber length of > about 4 mm. The second group of glass fibers may have a mean fiber length of > about 4.5 mm. The second group of glass fibers may have a mean fiber length of > about 5 mm. The second group of glass fibers may have a mean fiber length of > about 5.5 mm.

[0090] The second group of glass fibers may have a mean fiber length < about 10 mm. The second group of glass fibers may have a mean fiber length of < about 9.5 mm. The second group of glass fibers may have a mean fiber length of < about 9 mm. The second group of glass fibers may have a mean fiber length of < about 8.5 mm. The second group of glass fibers may have a mean fiber length of < about 8 mm. The second group of glass fibers may have a mean fiber length of < about 7.5 mm. The second group of glass fibers may have a mean fiber length of < about 7 mm. The second group of glass fibers may have a mean fiber length of < about 6.5 mm.

[0091] The second group of glass fibers may have a mean fiber length of about 6 mm.

[0092] Any suitable wt% ratio of glass fibers may be used provided the final coated non-woven fibrous mat retains its low air permeability and performance in the final application, notably in terms of resistance to rain and humidity. The ratio of the first group of glass fibers (having a larger average fiber diameter than the other group) : the second group of glass fibers (having a smaller average fiber diameter than the other group) may be in the range of about 5 : about 95 wt% to about 95 : about 5 wt%. The ratio of the first group of glass fibers : the second group of glass fibers may be about 10 : about 90 wt%. The ratio of the first group of glass fibers : the second group of glass fibers may be about 20 : about 80 wt%. The ratio of the first group of glass fibers : the second group of glass fibers may be about 30 : about 70 wt%. The ratio of the first group of glass fibers : the second group of glass fibers may be about 40 : about 60 wt%. The ratio of the first group of glass fibers : the second group of glass fibers may be about 50 : about 50 wt%. The ratio of the first group of glass fibers : the second group of glass fibers may be about 60 : about 40 wt%. The ratio of the first group of glass fibers : the second group of glass fibers may be about 70 : about 30 wt%. The ratio of the first group of glass fibers : the second group of glass fibers may be about 80 : about 20 wt%. The ratio of the first group of glass fibers : the second group of glass fibers may be about 10 : about 90 wt%.

[0093] Irrespective of the number of groups of glass fibers in the precursor mat, the glass fibers may comprise

[0094] SiO2 in a range from about 50 to about 65 wt% of the total wt% of the glass composition. The glass fibers may comprise SiO2 in a range from about 51 to about 62 wt% of the total wt% of the glass composition. The glass fibers may comprise SiO2 in a range from about 52 to about 62 wt% of the total wt% of the glass composition, such as about 52 to about 56 wt% of the total wt% of the glass composition or about 55 wt% to about 60.4 wt% of the total wt% of the glass composition. The glass fibers may comprise SiO2 in a range from about 54 to about 62 wt% of the total wt% of the glass composition. The glass fibers may comprise SiO2 in about 58 wt% of the total wt% of the glass composition. The glass fibers may comprise SiO2 in about 59 wt% of the total wt% of the glass composition. The glass fibers may comprise SiO2 in about 60 wt% of the total wt% of the glass composition, such as about 60.1 wt%.

[0095] The glass fibers may comprise AI2O3 in a range from about 7 to about 25 wt% of the total wt% of the glass composition. The glass fibers may comprise AI2O3 in a range from about 7 to about 20 wt% of the total wt% of the glass composition. The glass fibers may comprise AI2O3 in a range from about 19 to about 25 wt% of the total wt% of the glass composition. The glass fibers may comprise AI2O3 in a range from about 9 to about 15 wt% of the total wt% of the glass composition. The glass fibers may comprise AhOs in a range from about 12 to about 16 wt% of the total wt% of the glass composition, such as about 12 to about 15 wt% of the total wt% of the glass composition. The glass fibers may comprise AI2O3 in a range from about 17 to about 20 wt% of the total wt% of the glass composition. The glass fibers may comprise AI2O3 in about 11.5 wt% of the total wt% of the glass composition, such as about 11 .6 wt%. The glass fibers may comprise AI2O3 in about 12 wt% of the total wt% of the glass composition, such as about 12.1 wt%. The glass fibers may comprise AI2O3 in about 13 wt% ofthe total wt% of the glass composition, such as about 13.2 wt%.

[0096] The glass fibers may contain B2O3 i.e. the glass fibers are boron-containing glass fibers. The glass fibers may comprise B2O3 in a range from about 1 wt% to about 12 wt% of the total wt% of the glass composition. The glass fibers may comprise B2O3 in a range from about 4 to about 6 wt% of the total wt% of the glass composition. The glass fibers may comprise B2Os in a range from about 5 to about 10 wt% of the total wt% of the glass composition. The glass fibers may comprise B2Os in a range from about 7 to about 12 wt% of the total wt% of the glass composition. Without wishing to be bound by theory, boron-containing glass fibers typically have lower softening points than boron-free glass fibers. The process for preparing the fibers typically utilise less energy than the boron-free fibers (because the glass melt typically has a lower softening point). The lower softening point of the boron-containing glass fibers may be of use in the application of the fibers.

[0097] The glass fibers may comprise substantially no B2O3 i.e. the glass fibers may be substantially boron- free fibers. The glass fibers may contain less than 0.2 wt% B2O3 of the total wt% of the glass composition. The glass fibers may comprise no B2O3 i.e. the glass fibers may be boron-free fibers. Without wishing to be bound by theory, boron-free or substantially boron-free glass fibers are more environmentally friendly than the boron-containing glass fibers as melts from which the fibers are made do not emit boron into the environment during processing. The fibers themselves typically have higher softening points than boron-containing fibers which may be of use in the application of the fibers.

[0098] The glass fibers may comprise CaO in a range from about 7 to about 30 wt% of the total wt% of the glass composition. The glass fibers may comprise CaO in a range from about 7 to about 12 wt% of the total wt% of the glass composition. The glass fibers may comprise CaO in a range from about 12 to about 30 wt% of the total wt% of the glass composition. The glass fibers may comprise CaO in a range from about 16 to about 25 wt% of the total wt% of the glass composition, such as about 17 to about 25 wt% of total wt% of the glass composition. The glass fibers may comprise CaO in a range from about 21 to about 23 wt% of the total wt% of the glass composition. The glass fibers may comprise CaO in a range from about 24 to about 30 wt% of the total wt% of the glass composition. The glass fibers may comprise CaO in about 21 .7 wt% of the total wt% of the glass composition. The glass fibers may comprise CaO in about 22 wt% of the total wt% of the glass composition. The glass fibers may comprise CaO in about 22.1 wt% of the total wt% of the glass composition. The glass fibers may comprise CaO in about 22.6 wt% of the total wt% of the glass composition.

[0099] The glass fibers may comprise MgO in a range from about 0.1 to about 15 wt% of the total wt% of the glass composition. The glass fibers may comprise MgO in a range from about 0.1 to about 8 wt% of the total wt% of the glass composition, such as about 0.1 to about 4 wt% of the total wt% of the glass composition. The glass fibers may comprise MgO in a range from about 8 to about 15 wt% of the total wt% of the glass composition. The glass fibers may comprise MgO in a range from about 0.1 to about 5 wt% of the total wt% of the glass composition. The glass fibers may comprise MgO in a range from about 0.4 to about 4 wt% of the total wt% of the glass composition. The glass fibers may comprise MgO in about 2 wt% of the total wt% of the glass composition. The glass fibers may comprise MgO in about 3.1 wt% of the total wt% of the glass composition. The glass fibers may comprise MgO in about 3.4 wt% of the total wt% of the glass composition.

[0100] The glass fibers may comprise substantially no MgO i.e. the glass fibers may be substantially magnesium-free fibers. The glass fibers may comprise no MgO i.e. the glass fibers may be magnesium- free fibers. The glass fibers may comprise ZnO in a range from about 0.1 to about 4 wt% of the total wt% of the glass composition. The glass fibers may comprise ZnO in a range from about 0.5 to about 1 wt% of the total wt% of the glass composition, such as about 1 wt%.

[0101] The glass fibers may comprise ZnO in a range from about 2 to about 5 wt% of the total wt% of the glass composition. The glass fibers may comprise ZnO in a range from about 1 to about 4 wt% of the total wt% of the glass composition, such as about 1.1 to about 3 wt%. The glass fibers may comprise ZnO in about 2.9 wt% of the total wt% of the glass composition.

[0102] The glass fibers may comprise substantially no ZnO i.e. the glass fibers may be substantially zinc-free fibers. The glass fibers may comprise no ZnO i.e. the glass fibers may be zinc-free fibers.

[0103] The glass fibers may comprise BaO in a range from about 0.1 to about 3 wt% of the total wt% of the glass composition. The glass fibers may comprise BaO in a range from about 0.5 to about 1 wt% of the total wt% of the glass composition, such as about 1 wt%. The glass fibers may comprise BaO in a range from about 1 to about 3 wt% of the total wt% of the glass composition, such as about 1 .1 to about 3 wt%.

[0104] The glass fibers may comprise substantially no BaO i.e. the glass fibers may be substantially barium- free fibers. The group of glass fibers may comprise no BaO i.e. the glass fibers may be barium-free fibers.

[0105] The glass fibers may comprise IJ2O in a range from about 0.1 to about 1 wt% of the total wt% of the glass composition. The glass fibers may comprise IJ2O in a range from about 0.1 to about 0.4 wt% of the total wt% of the glass composition. The glass fibers may comprise IJ2O in a range from about 0.5 to about 1 wt% of the total wt% of the glass composition.

[0106] The glass fibers may comprise substantially no IJ2O i.e. the glass fibers may be substantially lithium- free fibers. The glass fibers may contain less than 0.2 wt% U2O of the total wt% of the glass composition. The glass fibers may comprise no IJ2O i.e. the glass fibers may be lithium-free fibers.

[0107] The glass fibers may comprise Na2<D and K2O in a range from about 0.1 to about 5 wt% of the total wt% of the glass composition. The glass fibers may comprise Na2<D and K2O in a range from about 0.1 to about 4 wt% of the total wt% of the glass composition, such as about 0.5 to about 4 wt% of the total wt% of the glass composition. The glass fibers may comprise a total of Na2<D and K2O in a range from about 0.1 to about 2 wt% of the total wt% of the glass composition, such as about 0.1 to about 1 wt% of the total wt% of the glass composition. The glass fibers may comprise a total of Na2<D and K2O in a range from about 0.1 to about 0.3 wt% of the total wt% of the glass composition. The glass fibers may comprise Na2<D and K2O in about 0.1 to about 0.2 wt% of the total wt% of the glass composition. The glass fibers may comprise Na2<D and K2O in about 0.9 wt% of the total wt% of the glass composition. The glass fibers may comprise Na2<D and K2O in about 0.8 wt% of the total wt% of the glass composition. The glass fibers may comprise Na2<D and K2O in about 1 .2 wt% of the total wt% of the glass composition.

[0108] The glass fibers may comprise substantially no Na2<D or K2O i.e. the glass fibers may be substantially sodium- and potassium-free fibers. The glass fibers may comprise no Na2<D or K2O i.e. the glass fibers may be sodium- and potassium-free fibers.

[0109] The glass fibers may comprise TiO2 in a range from about 0.1 to about 5 wt% of the total wt% of the glass composition. The glass fibers may comprise TiO2 in a range from about 0.1 to about 4 wt% of the total wt% of the glass composition. The glass fibers may comprise T1O2 in a range from about 0.1 to about 0.2 wt% of the total wt% of the glass composition, such as about 0.1 to about 1 .5 wt%. The glass fibers may comprise TiO2 in a ange from about 0.2 to about 0.5 wt% of the total wt% of the glass composition. The glass fibers may comprise TiO2 in about 0.5 wt% of the total wt% of the glass composition. The glass fibers may comprise TiO2 in about 1.5 wt% of the total wt% of the glass composition. The glass fibers may comprise TiO2 in about 2.5 wt% of the total wt% of the glass composition.

[0110] The glass fibers may comprise substantially no TiO2 i.e. the glass fibers may be substantially titanium- free fibers. The glass fibers may comprise no TiO2 i.e. the glass fibers may be titanium-free fibers.

[0111] The glass fibers may comprise ZrO2 in a range from about 0.1 to about 1 wt% of the total wt% of the glass composition. The glass fibers may comprise ZrO2 in a range from about 0.1 to about 0.4 wt% of the total wt% of the glass composition. The glass fibers may comprise ZrO2 in a range from about 0.5 to about 1 wt% of the total wt% of the glass composition.

[0112] The glass fibers may comprise substantially no ZrO2 i.e. the glass fibers may be substantially zirconium- free fibers. The glass fibers may comprise no ZrO2 i.e. the glass fibers may be zirconium-free fibers.

[0113] The glass fibers may comprise Fe2<D3 in a range from about 0.1 to about 2 wt% of the total wt% of the glass composition. The glass fibers may comprise Fe2<D3 in a range from about 0.1 to about 0.8 wt% of the total wt% of the glass composition. The glass fibers may comprise Fe2<D3 in a range from about 0.2 to about 0.4 wt% of the total wt% of the glass composition. The glass fibers may comprise Fe2<D3 in about 0.1 wt% of the total wt% of the glass composition. The glass fibers may comprise Fe2<D3 in about 0.2 wt% of the total wt% of the glass composition.

[0114] The glass fibers may comprise substantially no Fe2<D3 i.e. the glass fibers may be substantially iron-free fibers. The glass fibers may comprise no Fe2<D3 i.e. the glass fibers may be iron-free fibers.

[0115] The glass fibers may comprise F2 in a range from about 0.1 to about 2 wt% of the total wt% of the glass composition. The glass fibers may comprise F2 in a range from about 0.1 to about 1 wt% of the total wt% of the glass composition. The glass fibers may comprise F2 in a range from about 0.2 to about 0.7 wt% of the total wt% of the glass composition. The glass fibers may comprise F2 in about 0.1 wt% of the total wt% of the glass composition.

[0116] As described above, the precursor mat may be PFAS-free. The glass fibers in the precursor mat may comprise F2 but the precursor mat may still be PFAS-free.

[0117] The glass fibers may comprise substantially no F2 i.e. the glass fibers may be substantially fluoride-free fibers. The glass fibers may contain less than 0.2 wt% F2 of the total wt% of the glass composition. The glass fibers may comprise no F2 i.e. the glass fibers may be fluoride-free fibers. Without wishing to be bound by theory, fluoride-free or substantially fluoride-free fibers are more environmentally friendly than fluoride-containing fibers.

[0118] The glass fibers may comprise a composition comprising:

[0119] While various components in the glass may be expressed as a range, the total wt% of the composition adds up to 100 wt%.

[0120] The glass fibers may comprise boron-containing E-glass, boron-free E-glass, ECR-glass, H glass, or a mixture thereof. The glass fibers may comprise boron-containing E-glass fibers. The glass fibers may comprise boron-free E-glass fibers. The glass fibers may comprise ECR-glass fibers. The glass fibers may comprise a mixture of boron-containing E-glass, and boron-free E-glass fibers. The glass fibers may comprise a mixture of boron-containing E-glass, and ECR-glass fibers. The glass fibers may comprise a mixture of boron-free E-glass fibers, and ECR-glass fibers. The glass fibers may comprise a mixture of boron-containing E-glass, boron-free E-glass fibers, and ECR-glass fibers. The glass fibers may comprise H glass.

[0121] The composition of boron-containing E-glass may comprise:

[0122] While various components in the E-glass may be expressed as a range, the total wt% of the composition adds up to 100 wt%. The composition of boron-free E-glass may comprise: While various components in the E-glass may be expressed as a range, the total wt% of the composition adds up to 100 wt%. In this instance, the boron-free E-glass does not comprise F2. Alternatively or in addition, the composition of boron-free E-glass may comprise:

[0123] While various components in the E-glass may be expressed as a range, the total wt% of the composition adds up to 100 wt%. In this instance, the boron-free E-glass comprises F2.

[0124] The composition of ECR-glass may comprise:

[0125] While various components in the ECR-glass may be expressed as a range, the total wt% of the composition adds up to 100 wt%. In this instance, the ECR-glass comprises no or substantially no B2O3 nor F2. Boron-free ECR-glass fibers are commercially available from Owens Corning as Advantex™ glass fibers.

[0126] H glass and the method by which it can be prepared is disclosed in US11214512, the content of which is incorporated herein by reference in its entirety. The composition of H glass may comprise:

[0127] SiO2 in an amount from 55.0 to 60.4% by weight;

[0128] AI2O3 in an amount from 19.0 to 25.0% by weight;

[0129] CaO in an amount from 7 to 12.0% by weight;

[0130] MgO in an amount from 8.0 to 15.0% by weight;

[0131] Na2O in an amount from 0 to 1 .0% by weight; and

[0132] TiO2 in an amount from 0.0 to 1 .5% by weight, expressed as percentages by weight based on the weight of the entire composition, wherein the weight percent ratio of AhOs / MgO is less than 2.0, wherein the combined amounts of SiO2, AI2O3, MgO, and CaO is at least 98% by weight and less than 99.5% by weight, wherein the sum of the amounts of B2O3, U2O, and fluorine is less than 0.2% by weight, and wherein said glass composition has a fiberizing temperature no greater than 2,500° F.

[0133] The composition of H glass may comprise 19.5 to 21 % by weight AI2O3.

[0134] The combined amounts in H glass of MgO and CaO is greater than 20% by weight.

[0135] The combined amounts in H glass of MgO and CaO is less than 22% by weight.

[0136] The weight percent ratio in H glass ofAhOs / MgO is no greater than 1.8.

[0137] The combined amounts in H glass of Fe20s, TiO2, K2O, and Na2O is below 1 .5% by weight.

[0138] The composition of H glass is free or substantially free of B2O3.

[0139] The composition of H glass is free of IJ2O.

[0140] When the precursor mat comprises polyester fibers, any suitable polyester fibers may be used provided the final coated non-woven fibrous mat retains its low air permeability and water resistance. The polyester fibers may be aliphatic-aryl polyester fibers which are known to the skilled person, such as poly(ethylene terephthalate) (PET) fibers, poly(butylene terephthalate) (PBT) fibers, poly(hexamethylene terephthalate) (PHT) fibers, polypropylene terephthalate) (PTT) fibers, or mixture thereof.

[0141] The polyester fibers may not comprise recycled polyester fibers i.e. the polyester fibers may not have been subjected to any processing other than for their production.

[0142] The polyester fibers may have a mean fiber diameter as described below and a mean fiber length as described below.

[0143] The polyester fibers may have a mean fiber diameter in the range of > about 1 pm and < about 15 pm. The polyester fibers may have a mean fiber diameter in the range of > about 3 pm and < about 10 pm.

[0144] The polyester fibers may have a mean fiber diameter of > about 3.5 pm. The polyester fibers may have a mean fiber diameter of > about 4 pm. The polyester fibers may have a mean fiber diameter of > about

[0145] 4.5 pm. The polyester fibers may have a mean fiber diameter of > about 5 pm. The polyester fibers may have a mean fiber diameter of > about 5.5 pm. The polyester fibers may have a mean fiber diameter of > about 6 pm.

[0146] The polyester fibers may have a mean fiber diameter < about 9.5 pm. The polyester fibers may have a mean fiber diameter of < about 9 pm. The polyester fibers may have a mean fiber diameter of < about

[0147] 8.5 pm. The polyester fibers may have a mean fiber diameter of < about 8 pm. The polyester fibers may have a mean fiber diameter of < about 7.5 pm. The polyester fibers may have a mean fiber diameter of < about 7 pm.

[0148] The polyester fibers may have a mean fiber diameter of about 6 to about 7 pm, such as about 6 pm.

[0149] The polyester fibers may have a mean fiber length in the range of > about 1 mm and < about 15 mm. The polyester fibers may have a mean fiber length in the range of > about 3 mm and < about 10 mm. The polyester fibers may have a mean fiber length of > about 3.5 mm. The polyester fibers may have a mean fiber length of > about 4 mm. The polyester fibers may have a mean fiber length of > about 4.5 mm. The polyester fibers may have a mean fiber length of > about 5 mm. The polyester fibers may have a mean fiber length of > about 5.5 mm. The polyester fibers may have a mean fiber length of > about 6 mm.

[0150] The polyester fibers may have a mean fiber length < about 9.5 mm. The polyester fibers may have a mean fiber length of < about 9 mm. The polyester fibers may have a mean fiber length of < about 8.5 mm. The polyester fibers may have a mean fiber length of < about 8 mm. The polyester fibers may have a mean fiber length of < about 7.5 mm. The polyester fibers may have a mean fiber length of < about 7 mm. The polyester fibers may have a mean fiber length of about 6-7 mm.

[0151] Any suitable wt% ratio of glass fibers : polyester fibers may be used provided the final coated nonwoven fibrous mat retains its low air permeability and performance in the final application, notably in terms of resistance to rain and humidity. The ratio of glass fibers : polyester fibers may be in the range of about 50 : about 50 wt% to about 90 : about 10 wt%. The ratio of glass fibers : polyester fibers may be about 55 : about 45 wt%. The ratio of glass fibers : polyester fibers may be about 60 : about 40 wt%. The ratio of glass fibers : polyester fibers may be about 65 : about 35 wt%. The ratio of glass fibers : polyester fibers may be about 70 : about 30 wt%. The ratio of glass fibers : polyester fibers may be about 80 : about 20 wt%. The ratio of glass fibers : polyester fibers may be about 85 : about 15 wt%. The ratio of glass fibers : polyester fibers may be about 90 : about 10 wt%.

[0152] The ratio of glass fibers : polyester fibers may be about 75 : about 25 wt%.

[0153] The total wt% of the glass fibers and the polyester fibers adds up to 100 wt%.

[0154] The first binder and coating composition are applied in two separate stages during the manufacture of the coated non-woven fibrous mat. The first binder, or combination thereof, is applied first in the formation of the precursor mat and dried, and the coating composition (comprising the aqueous composition defined herein) is applied secondly in the formation of the final coated non-woven fibrous mat and dried.

[0155] The first binder may be selected from one or more (e.g. 1 , 2, 3, 4, 5, or more) urea formaldehyde resins, such as modified urea formaldehyde resins.

[0156] Alternatively, the first binder may be selected from a formaldehyde-free (or no-added formaldehyde (“NAF”)) binder. Binders which are free of added formaldehyde are environmentally friendly i.e. “green”.

[0157] The first binder may be selected from one or more (e.g. 1 , 2, 3, 4, 5, or more) polycarboxylic acid binders, polyvinyl alcohol binders, or combination thereof.

[0158] The first binder may be a water-soluble or water-dispersible binder. The binder may be a water-soluble binder. The binder may be a water-dispersible binder. The binder composition may comprise one or more of any water-based emulsion or solution.

[0159] The polycarboxylic acid binder may be a homopolymer or copolymer prepared from one or more (e.g. 1 , 2, 3, 4, 5 or more) unsaturated carboxylic acid compounds including but not necessarily limited to, acrylic acid, methacrylic acid, crotonic acid, isocrotonic acid, maleic acid, cinnamic acid, 2-methylmaleic acid, itaconic acid, 2-methylitaeonic acid, a,p-methyleneglutaric acid, and the like. Methods for polymerising these acids are known to the skilled person. In this instance, the polycarboxylic acid binder is a homopolymer or copolymer comprising at least one or more (e.g. 1 , 2, 3, 4, or 5) repeat units, and the or each repeat unit comprises a -COOH group.

[0160] Alternatively, the polycarboxylic acid binder may be prepared from unsaturated anhydrides including, but not necessarily limited to, maleic anhydride, methacrylic anhydride, and the like, as well as mixtures thereof. Methods for polymerising these anhydrides are known to the skilled person. In this instance, the polycarboxylic acid binder is a homopolymer or copolymer comprising at least one or more (e.g. 1 , 2, 3, 4, or 5) repeat units, and the or each repeat unit comprises a -CO-O-CO- group.

[0161] Alternatively or in addition, the polycarboxylic acid binder may comprise a homopolymer or copolymer prepared from one or more (e.g. 1 , 2, 3, 4, 5 or more) unsaturated carboxylic acid ester compounds including, but not necessarily limited to, methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, methyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, glycidyl methacrylate, vinyl acetate, and the like. Methods for preparing these polymers are known to the skilled person. In this instance, the polycarboxylic acid binder is a homopolymer or copolymer comprising at least one or more (e.g. 1 , 2, 3, 4, or 5) repeat units, and the or each repeat unit comprises a -COOR group, and R is selected from the group consisting of methyl, ethyl, butyl (n-, i-, or t-), and 2,3-epoxypropyl as appropriate.

[0162] When the polycarboxylic acid binder comprises a mixture of a polymer (e.g. a homo- or co-polymer) of an unsaturated carboxylic acid (e.g. polyacrylic acid binder) and a polymer (e.g. a homo- or co-polymer) of an unsaturated carboxylic acid ester (e.g. polymethyl methacrylate), the wt% ratio of the polymer of the unsaturated carboxylic acid to the polymer of the unsaturated carboxylic acid ester may be in the range of about 1 : about 0.01 wt% to about 1 : about 1 wt% of the total solids in the binder composition. The wt% ratio of the polymer of the unsaturated carboxylic acid to the polymer of the unsaturated carboxylic acid ester may be in the range of about 1 : about 0.1 wt% to about 1 : about 0.8 wt% of the total solids in the binder composition. The wt% ratio of the polymer of the unsaturated carboxylic acid to the polymer of the unsaturated carboxylic acid ester may be in the range of about 1 : about 0.2 wt% to about 1 : about 0.5 wt% of the total solids in the binder composition. The wt% ratio of the polymer of the unsaturated carboxylic acid (e.g. polyacrylic acid binder) to the polymer of the unsaturated carboxylic acid ester (e.g. polymethyl methacrylate) may be about 1 : about 0.4 wt% of the total solids in the binder composition.

[0163] The polycarboxylic acid binder may be a homopolymer or copolymer of polyacrylic acid. The polycarboxylic acid binder is a homopolymer of polyacrylic acid i.e. the polymer is synthesised from acrylic acid. The weight average molecular weight (Mw) of the polycarboxylic acid binder, such as polyacrylic acid binder or polymethyl methacrylate binder, may be less than 10000 g / mole, such as less than 5000 g / mole, and for example about 3000 g / mole or less, e.g. about 2000 g / mole.

[0164] The polycarboxylic acid binder may comprise polymethyl methacrylate. The polycarboxylic acid binder may comprise polyacrylic acid and polymethyl methacrylate.

[0165] The pH of the first binder may be low, for example, about 3 or less, such as about 2.5 or less, e.g. about 2 or less. The pH of the binder can be adjusted by adding a suitable acid, such as sulfuric acid. The low pH of the binder can provide processing advantages. An example of the processing advantages include a reduction in cure temperature or time. The pH of the first binder may be about pH 2 to about pH 3.

[0166] The first binder, or combination thereof, may additionally contain a polyol containing at least two hydroxyl groups. Any suitable polyol may be used provided the polyol is sufficiently non-volatile such that it will substantially remain available for reaction with the polyacid in the composition during heating and curing operations. The polyol may be a compound with a molecular weight less than about 1000 and bearing at least two hydroxyl groups such as ethylene glycol, glycerol, penta erythritol, trimethylol propane, sorbitol, sucrose, glucose, resorcinol, catechol, pyrogallol, glycollated ureas, 1 ,4-cyclohexane diol, diethanolamine, or triethanolamine.

[0167] The polyol may be glycerol.

[0168] When the polycarboxylic acid binder comprises a mixture of a polymer (e.g. a homo- or co-polymer) of an unsaturated carboxylic acid and a polyol, the wt% ratio of the unsaturated carboxylic acid polymer to polyol may be in the range of about 1 : about 0.01 wt% to about 1 : about 1 wt% of the total solids in the binder composition. The wt% ratio of the unsaturated carboxylic acid polymer to polyol may be in the range of about 1 : about 0.1 wt% to about 1 : about 0.8 wt% of the total solids in the binder composition. The wt% ratio of the unsaturated carboxylic acid polymer to polyol may be in the range of about 1 : about 0.2 wt% to about 1 : about 0.5 wt% of the total solids in the binder composition. The wt% ratio of the unsaturated carboxylic acid polymer (e.g. polyacrylic acid binder) to polyol (e.g. glycerol) may be about 1 : about 0.3 wt% of the total solids in the binder composition, such as about 1 : 0.25 wt% of the total solids in the binder composition.

[0169] The first binder may be a combination of polyacrylic acid, polymethyl methacylate, and glycerol. The first binder may be a combination of (a) polyacrylic acid and glycerol, and (b) polymethyl methacrylate latex. The wt% ratio of polyacrylic acid : glycerol may be about 75% to about 25% of the total solids in the binder composition. The ratio of (a) : (b) may be about 75% to about 25% of the total solids in the binder composition. The final wt% ratio of polyacrylic acid : glycerol : polymethyl methacrylate overall may be about 56% : about 19% : about 25% of the total solids in the binder composition.

[0170] In certain embodiments, the polyol does not comprise a -hydroxyalkylamide group. Examples of such polyols, include but are not limited to, bis[N,N-di(hydroxyethyl)]adipamide. The first binder may be a polyvinyl alcohol binder. Suitable polyvinyl alcohol binders are as described herein with respect to the second binder.

[0171] The % hydrolysis may be > about 98 to 99%. In this instance, the polyvinyl alcohol binder has a high purity, and is particularly suitable for use in coated non-woven fibrous mats in polyisocyanurate foam boards.

[0172] The polyvinyl alcohol binder may be liquid or a solid. When the polyvinyl alcohol binder is a powder, it may be co-cast with the blend of glass fibers in the aqueous solution.

[0173] The polycarboxylic acid binder may be a copolymer prepared from one or more (e.g. 1 , 2, 3, 4, 5 or more) unsaturated carboxylic acid compounds and one or more (e.g. 1 , 2, 3, 4, 5 or more) aryl vinyl compounds. The unsaturated carboxylic acid include but not necessarily limited to, acrylic acid, methacrylic acid, crotonic acid, isocrotonic acid, maleic acid, cinnamic acid, 2-methylmaleic acid, itaconic acid, 2-methylitaeonic acid, a,p-methyleneglutaric acid, and the like. The aryl vinyl compounds include but are not limited to, styrene, methylstyrene (2-, 3-, or 4-), ethylstyrene (2-, 3-, or 4-), n- butylstyrene (2-, 3-, or 4-), iso-butylstyrene (2-, 3-, or 4-), tert-butylstyrene (2-, 3-, or 4-), a- methylstyrene (also known as isopropenylbenzene), p-methylstyrene (also known as propenylbenzene). Methods for preparing these copolymers are known to the skilled person. In this instance, the polycarboxylic acid binder is a copolymer comprising (a) a repeat unit comprising a - COOH group, and (b) a repeat unit comprising a substituted or unsubstituted styrenyl group.

[0174] The first binder may be styrene acrylic latex. In this instance, the copolymer is prepared from an unsaturated carboxylic acid which is acrylic acid, and an aryl vinyl compound which is styrene.

[0175] The wt% of the first binder, or combination thereof, may be in the range of about 1 wt% to about 90 wt% of the total solids in the precursor mat, such as about 5 wt% to about 50 wt% of the total solids in the precursor mat. The wt% of the first binder, or combination thereof, may be in the range of about 10 wt% to about 40 wt% of the total solids in the precursor mat.

[0176] The wt% of the first binder, or combination thereof, may be > about 10 wt% of the total solids in the precursor mat. The wt% of the first binder, or combination thereof, may be > about 11 wt% of the total solids in the precursor mat. The wt% of the first binder, or combination thereof, may be > about 12 wt% of the total solids in the precursor mat. The wt% of the first binder, or combination thereof, may be > about 13 wt% of the total solids in the precursor mat. The wt% of the first binder, or combination thereof, may be > about 14 wt% of the total solids in the precursor mat.

[0177] The wt% of the first binder, or combination thereof, may be < about 35 wt% of the total solids in the precursor mat. The wt% of the first binder, or combination thereof, mat may be < about 30 wt% of the total solids in the precursor mat. The wt% of the first binder, or combination thereof, may be < about 25 wt% of the total solids in the precursor mat.

[0178] The wt% of the first binder, or combination thereof, may be in the range of about 15 wt% to about 25 wt% of the total solids in the precursor mat.

[0179] The wt% of the first binder, or combination thereof, may be about 23 wt% of the total solids in the precursor mat.

[0180] The weight of the precursor mat (i.e. the weight of the first binder, glass fibers and polyester fibers (if any)) may be in the range of about 30 to about 170 gsm (grams per square meter). The weight of the precursor mat may be in the range of about 40 to about 150 gsm. The weight of the precursor mat may be > about 40 gsm. The weight of the precursor mat may be > about 45 gsm. The weight of the precursor mat may be > about 50 gsm. The weight of the precursor mat may be > about 55 gsm. The weight of the precursor mat may be > about 60 gsm.

[0181] The weight of the precursor mat may be < about 170 gsm. The weight of the precursor mat may be < about 165 gsm. The weight of the precursor mat may be < about 160 gsm. The weight of the precursor mat may be < about 155 gsm. The weight of the precursor mat may be < about 150 gsm. The weight of the precursor mat may be < about 140 gsm. The weight of the precursor mat may be < about 135 gsm. The weight of the precursor mat may be < about 130 gsm.

[0182] The weight of the precursor mat may be in the range of about 60 to about 130 gsm.

[0183] The weight of the precursor mat may be about 65 gsm.

[0184] A coating coats the precursor mat. The coating comprises no or substantially no water i.e. the coating is dry. The amounts of second binder in the coating, inorganic filler (if any), and optional additives (if any) may each be described as a percent weight based on the total solids in the dried coating composition. The percent weight of each component of the dried composition will add up to 100 wt% total solids in the dried coating composition.

[0185] The dried composition may comprise the second binder in about 100 wt% of the total solids in the dried composition i.e. the dried composition may comprise solely the second binder. When the second binder is a PVOH, the resulting coated non-woven fibrous mat may be transparent.

[0186] Alternatively, the dried composition may comprise the second binder in a range of about 50 wt% to about 100 wt% of the total solids in the dried composition. The dried composition may comprise the second binder in an amount of > about 10 wt% total solids in the dried composition, such as > about 50 wt% total solids in the dried composition. The dried composition may comprise the second binder in a range of about 52 wt% to about 95 wt% of the total solids in the dried composition.

[0187] The dried composition may comprise the second binder in an amount > 10 wt% of the total solids in the dried composition. The dried composition may comprise the second binder in an amount > 20 wt% of the total solids in the dried composition. The dried composition may comprise the second binder in an amount > 30 wt% of the total solids in the dried composition. The dried composition may comprise the second binder in an amount > 40 wt% of the total solids in the dried composition. The dried composition may comprise the second binder in an amount > 50 wt% of the total solids in the dried composition. The dried composition may comprise the second binder in an amount > 54 wt% of the total solids in the dried composition. The dried composition may comprise the second binder in an amount > 55 wt% of the total solids in the dried composition. The dried composition may comprise the second binder in an amount > 60 wt% of the total solids in the dried composition. The dried composition may comprise the second binder in an amount > 65 wt% of the total solids in the dried composition.

[0188] The dried composition may comprise the second binder in an amount < about 100 wt% of the total solids in the dried composition. The dried composition may comprise the second binder in an amount < about 99 wt% of the total solids in the dried composition. The dried composition may comprise the second binder in an amount < 95 wt% of the total solids in the dried composition. The dried composition may comprise the second binder in an amount < 90 wt% of the total solids in the dried composition. The dried composition may comprise the second binder in an amount < 85 wt% of the total solids in the dried composition. The dried composition may comprise the second binder in an amount < 80 wt% of the total solids in the dried composition. The dried composition may comprise the second binder in an amount < 75 wt% of the total solids in the dried composition.

[0189] The dried composition may comprise the second binder in a range of about 50 wt% to about 70 wt%, such as about 65 wt% to about 75 wt%. The dried composition may comprise the second binder in about 70 wt% of the total solids in the dried composition. The dried composition may comprise the second binder in about 50 wt% of the total solids in the dried composition.

[0190] The coating composition may comprise a filler. A filler may also be referred to as a mineral pigment or inorganic filler. Any suitable filler may be used. Examples of fillers suitable for making coated mats include, but are not limited to talc, aluminum trihydrate (ATH), magnesium hydroxide (Mg(OH)2), vermiculite, antimony oxide, titanium dioxide, aluminium oxide (AI2O3), calcium carbonate (CaCOs) or a combination of any two or more of these substances.

[0191] The filler may be a flame retardant, such as aluminum trihydrate (ATH), or magnesium hydroxide (Mg(OH)2). A coated non-woven fibrous mat comprising a flame retardant is beneficial when the mat is used in polyisocyanurate foam boards. ATH has fire retardant and smoke suppressing properties. It decomposes at about 220 °C, absorbing heat during the decomposition process while releasing water vapour.

[0192] The filler (such as ATH) may also be an opacity modifier i.e. the filler may make the coated non-woven fibrous mat less transparent and more opaque. The opacity of the coated non-woven fibrous mat may be measured in accordance with TAPPI T425.

[0193] The filler may be calcium carbonate.

[0194] The dried composition may comprise an inorganic filler in a range of about 1 wt% to about 90 wt% total solids in the dried composition.

[0195] The dried composition may comprise the filler in an amount of < about 90 wt% total solids in the dried composition. The dried composition may comprise the filler in an amount of < about 80 wt% total solids in the dried composition. The dried composition may comprise the inorganic filler in an amount of < about 70 wt% total solids in the dried composition. The dried composition may comprise the filler in an amount of < about 60 wt% total solids in the dried composition. The dried composition may comprise the filler in an amount of < about 50 wt% total solids in the dried composition. The dried composition may comprise the filler in an amount of < about 40 wt% total solids in the dried composition. The dried composition may comprise the filler in an amount of < about 35 wt% total solids in the dried composition.

[0196] The dried composition may comprise the filler in an amount of > about 1 wt% total solids in the dried composition. The dried composition may comprise the filler in an amount of > about 5 wt% total solids in the dried composition. The dried composition may comprise the filler in an amount of > about 10 wt% total solids in the dried composition. The dried composition may comprise the filler in an amount of > about 15 wt% total solids in the dried composition. The dried composition may comprise the filler in an amount of > about 20 wt% total solids in the dried composition. The dried composition may comprise the filler in an amount of > about 25 wt% total solids in the dried composition.

[0197] The dried composition may comprise the inorganic filler in a range of about 15 wt% to about 35 wt%, such as about 15 wt% or 30 wt% of the total solids in the dried composition.

[0198] The dried composition may comprise the inorganic filler in a range of about 25 wt% to about 35 wt%, such as about 30 wt% of the total solids in the dried composition.

[0199] The dried composition may comprise the inorganic filler in a range of about 20 wt% to about 60 wt%, such as about 30 wt%, or about 50 wt%, of the total solids in the dried composition. The filler (such as ATH) may also be an opacity modifier i.e. the filler may make the coated non-woven fibrous mat less transparent and more opaque. The coated non-woven fibrous mat of the present invention may be substantially or completely opaque.

[0200] The dried coating may further comprise at least one additive (e.g. 1 , 2, 3, 4, 5, or more) selected from the group consisting of a biocide, defoamer, pigment, preservative, emulsion stabilizer, wetting and levelling agent, cross-linker, and combinations thereof. Any suitable additive may be used provided the or each additive do not adversely affect the properties of the coated non-woven mat. In particular, the or each additive shall not adversely affect the air permeability of the coated non-woven fibrous mat such that the coated non-woven fibrous mat exhibits an air permeability greater than 70 L / m2 / s as measured according to ASTM D737. A method for assessing the air permeability is provided in the Examples below.

[0201] The dried coating composition may consist essentially of the second binder (for example, the PVOH binder as described herein), the inorganic filler, optionally a defoamer, and optionally a viscosity modifier. The dried coating composition may consist of the second binder (for example, the PVOH binder as described herein), the inorganic filler, optionally a defoamer, and optionally a viscosity modifier.

[0202] Alternatively, the dried coating may contain no other optional additives. The dried coating composition therefore may consist essentially of the second binder (for example, the PVOH binder as described herein). The dried coating composition therefore may consist of the second binder (for example, the PVOH binder as described herein).

[0203] The weight of the dried coating may be in the range of about 10 to about 50 gsm (grams per square meter).

[0204] The weight of the dried coating may be > about 11 gsm. The weight of the dried coating may be > about 12 gsm. The weight of the dried coating may be > about 13 gsm. The weight of the dried coating may be > about 14 gsm. The weight of the dried coating may be > about 15 gsm.

[0205] The weight of the dried coating may be < about 50 gsm. The weight of the dried coating may be < about 45 gsm. The weight of the dried coating may be < about 40 gsm. The weight of the dried coating may be < about 39 gsm. The weight of the dried coating may be < about 38 gsm. The weight of the dried coating may be < about 37 gsm. The weight of the dried coating may be < about 36 gsm. The weight of the dried coating may be < about 35 gsm.

[0206] The weight of the dried coating may be in the range of about 15 to about 35 gsm, such as about 15 to about 25 gsm, or about 25 to about 35 gsm. In contrast to prior art coatings which utilise a heavy, mineral-coated glass non-woven mat, the coated non-woven mat of the present invention is lightweight. The total weight of the (dried) coated non-woven fibrous mat may be in the range of about 40 to about 220 gsm (grams per square meter). The total weight of the coated non-woven fibrous mat may be in the range of about 50 to about 200 gsm. The total weight of the coated non-woven fibrous mat may be > about 51 gsm. The total weight of the coated non-woven fibrous mat may be > about 57 gsm. The total weight of the coated non-woven fibrous mat may be > about 63 gsm. The total weight of the coated non-woven fibrous mat may be > about 69 gsm. The total weight of the coated non-woven fibrous mat may be > about 75 gsm.

[0207] The total weight of the coated non-woven fibrous mat may be < about 220 gsm. The total weight of the coated non-woven fibrous mat may be < about 210 gsm. The total weight of the coated non-woven fibrous mat may be < about 200 gsm. The total weight of the coated non-woven fibrous mat may be < about 193 gsm. The total weight of the coated non-woven fibrous mat may be < about 188 gsm. The total weight of the coated non-woven fibrous mat may be < about 177 gsm. The total weight of the coated non-woven fibrous mat may be < about 171 gsm. The total weight of the coated non-woven fibrous mat may be < about 165 gsm.

[0208] The total weight of the coated non-woven fibrous mat may be in the range of about 45 to about 165 gsm, such as about 45 to 155 gsm. The total weight of the coated non-woven fibrous mat may be in the range of about 75 to about 150 gsm, such as about 90 to about 100 gsm.

[0209] An air permeability test measures airflow through an area of substrate, such as the coated non-woven mat of the present invention. The coated non-woven fibrous mat may have an air permeability as measured at 100 mbar in accordance with ASTM D737. The coated non-woven fibrous mat of the present invention is highly air impermeable, which prevents foam bleed through during preparation of the polyisocyanurate foam boards. The coated non-woven fibrous mat may have an air permeability in the range of about 1 L.rrH.S'1to about 70 L.rrH.S'1(L.rr .S'1= L / m2 / second) measured in accordance with ASTM D737. The coated non-woven fibrous mat may have an air permeability > about 1 L.nrH.S’1. The coated non-woven fibrous mat may have an air permeability > about 2 L.rr .s1. The coated nonwoven fibrous mat may have an air permeability > about 3 L.rr .s'1. The coated non-woven fibrous mat may have an air permeability > about 4 L.rr .s-1. The coated non-woven fibrous mat may have an air permeability > about 5 L.rrH.s-1.

[0210] The coated non-woven fibrous mat may have an air permeability < about 70 L.nrH.S’1. The coated nonwoven fibrous mat may have an air permeability < about 60 L.rr .s1. The coated non-woven fibrous mat may have an air permeability < about 50 L.rrH.s1. The coated non-woven fibrous mat may have an air permeability < about 40 L.rr .S'1. The coated non-woven fibrous mat may have an air permeability < about 30 L.rr .s-1. The coated non-woven fibrous mat may have an air permeability < about 20 L.m_2.s'1. The coated non-woven fibrous mat may have an air permeability in the range of about 5 L.rr .s-1to about 65 L.m_2.s'1measured in accordance with ASTM D737, such as about 5 L.rrH.s-1to about 20 L.rrr 2.S-1.

[0211] Methods for Preparing the Coated Non-Woven Fibrous Mat

[0212] In another aspect, the present invention provides a method for manufacturing the coated non-woven fibrous mat of the present invention, the method comprising the steps of:

[0213] (v) providing a precursor mat comprising glass fibers and a first binder;

[0214] (vi) coating one major surface of the precursor mat with an aqueous composition with a reverse roll technique, wherein the aqueous composition comprises a second binder, wherein the second binder is a polyvinyl alcohol binder with a weight average molecular weight in the range of about 100000 g / mole to about 500000 g / mol; and

[0215] (vii) drying the coated precursor mat to form the coated non-woven fibrous mat, wherein the coated non-woven fibrous mat has an air permeability of < about 70 L / m2 / s as measured according to ASTM D737.

[0216] The precursor mat, glass fibers, polyester fibers (if any), first binder, second binder, polyvinyl alcohol binder, weight average molecular weight of the polyvinyl alcohol binder, filler (if any), coated non-woven fibrous mat, and air permeability are as described herein.

[0217] The polyvinyl alcohol binder has the advantage of being water-soluble on preparation of the aqueous composition that is coated onto at least one surface of the precursor veil. After drying, the aqueous composition forms a film that allows the coated non-woven fibrous mat to have a good performance in the targeted application, notably in terms of resistance to rain and humidity before render application. The resulting coated non-woven fibrous mat therefore is suitable for use in external thermal insulation composite systems (ETICs).

[0218] One major surface of the precursor mat is coated with the aqueous composition using reverse roll coating. A reverse roll technique is known to the skilled person. In this respect, three rollers are set up in parallel, and rotate in the same direction. A metering roller is suitably aligned next to an application roller. A support roller is suitably aligned next to the application roller. The precursor mat passes through a predetermined gap between the application roller and the support roller. The aqueous composition is deposited in the gap between the metering roller and the application roller. As the metering and application rollers rotate, the aqueous composition passes through a predetermined gap between the metering and application rollers, and adheres to the application roller. The aqueous composition which is adhered to the application roller is then coated onto one major surface of the precursor mat as the precursor mat passes through the rotating application and support rollers. A reverse roll coating technique is not an impregnation or classical size press method. The aqueous composition as described herein is not impregnated through the precursor mat when using the reverse roll coating method.

[0219] The present invention provides an aqueous composition for coating a non-woven fibrous mat. The aqueous composition comprises a binder. The binder is described as a “second binder” in connection with the coated non-woven fibrous mat.

[0220] The second binder is a polyvinyl alcohol binder with a weight average molecular weight in the range of about 100000 g / mole to about 500000 g / mol. The polyvinyl alcohol binder is as described above.

[0221] The viscosity of the aqueous composition is not particularly limiting provided (a) it is maintained high enough to ensure the reduction of the air permeability of the non-woven fibrous mat to < about 70 L / m2 / s as measured according to ASTM D737, (b) it is maintained high enough to ensure that the aqueous composition does not penetrate through the entire thickness of the non-woven mat, and (c) it is maintained low enough such that the non-woven fibrous mat can be suitably coated using a reverse roll coating (or wire bar, kiss roll, knife-over-air, or knife-over-air) technique.

[0222] The aqueous composition may have a viscosity in the range from > about 500 mPa.s to < about 5000 mPa.s (millipascal second) as measured at room temperature using a Brookfield synchronized-motor rotary viscometer. The aqueous composition may have a viscosity > about 500 mPa.s as measured at room temperature using a Brookfield synchronized-motor rotary viscometer. The aqueous composition may have a viscosity > about 600 mPa.s as measured at room temperature using a Brookfield synchronized-motor rotary viscometer. The aqueous composition may have a viscosity > about 700 mPa.s as measured at room temperature using a Brookfield synchronized-motor rotary viscometer. The aqueous composition may have a viscosity > about 800 mPa.s as measured at room temperature using a Brookfield synchronized-motor rotary viscometer. The aqueous composition may have a viscosity > about 900 mPa.s as measured at room temperature using a Brookfield synchronized-motor rotary viscometer. The aqueous composition may have a viscosity > about 1000 mPa.s as measured at room temperature using a Brookfield synchronized-motor rotary viscometer. The aqueous composition may have a viscosity > about 1100 mPa.s as measured at room temperature using a Brookfield synchronized-motor rotary viscometer.

[0223] The aqueous composition may have a viscosity < about 5000 mPa.s as measured at room temperature using a Brookfield synchronized-motor rotary viscometer. The aqueous composition may have a viscosity < about 4500 mPa.s as measured at room temperature using a Brookfield synchronized-motor rotary viscometer. The aqueous composition may have a viscosity < about 4000 mPa.s as measured at room temperature using a Brookfield synchronized-motor rotary viscometer. The aqueous composition may have a viscosity in the range from > about 1000 mPa.s and < about 5000 mPa.s as measured at room temperature using a Brookfield synchronized-motor rotary viscometer.

[0224] The aqueous composition exhibits shear thinning in the reverse roll coating technique (or other coating techniques described herein). The viscosities provided above therefore are shear thinned viscosities. The viscosity of the aqueous composition before it is exposed to the applied pressure of the rollers in the reverse roll technique may be greater than 2000 mPa.s, for example, the viscosity may be between 2000 mPa.s to about 5000 mPa.s.

[0225] The weight average molecular weight (Mw) of the polyvinyl alcohol binder is as described above.

[0226] The degree of hydrolysis of the polyvinyl alcohol binder is as described above.

[0227] Any suitable quantity of polyvinyl alcohol may be used in the aqueous composition provided sufficient polyvinyl alcohol is used to produce an aqueous composition having a suitable viscosity as described above.

[0228] The polyvinyl alcohol may be dissolved in water to provide the desired aqueous composition. The water used may be demineralised. Alternatively, the water may be tap water.

[0229] The mixture of polyvinyl alcohol and water may be agitated and / or heated to facilitate dissolution. The mixture may be agitated for any suitable period of time. The mixture may be heated at a suitable temperature (e.g. about 92 °C, such as about 85 °C) for any suitable period of time (e.g. about 4 hours, such as about 3 hours), provided the aqueous solution of polyvinyl alcohol is not heated for so long that the aqueous solution is adversely affected.

[0230] The wt% of the polyvinyl alcohol binder may be in the range of about 5 wt% to about 15 wt% of the total weight of the aqueous composition. The wt% of the polyvinyl alcohol binder may be > about 5.5 wt% of the total weight of the aqueous composition. The wt% of the polyvinyl alcohol binder may be > about 6 wt% of the total weight of the aqueous composition. The wt% of the polyvinyl alcohol binder may be > about 6.5 wt% of the total weight of the aqueous composition. The wt% of the polyvinyl alcohol binder may be > about 7 wt% of the total weight of the aqueous composition. The wt% of the polyvinyl alcohol binder may be > about 8 wt% of the total weight of the aqueous composition.

[0231] The wt% of the polyvinyl alcohol binder may be < about 15 wt% of the total weight of the aqueous composition. The wt% of the polyvinyl alcohol binder may be < about 14 wt% of the total weight of the aqueous composition. The wt% of the polyvinyl alcohol binder may be < about 13 wt% of the total weight of the aqueous composition. The wt% of the polyvinyl alcohol binder may be < about 12 wt% of the total weight of the aqueous composition. The wt% of the polyvinyl alcohol binder may be < about 11 wt% of the total weight of the aqueous composition.

[0232] The wt% of the polyvinyl alcohol binder may be in the range of about 8 wt% to about 11 wt% of the total weight of the aqueous composition, such as about 8 wt%, about 9 wt% about 10 wt%, or about 11 wt%, for example about 10 wt%.

[0233] The aqueous composition (and hence the coating of the coated non-woven fibrous mat) does not contain added poly- or per-fluoroalkyl substances (PFAS) as described above.

[0234] The composition is aqueous i.e. contains water. The quantity of water in the composition is not particularly limited provided the viscosity of the composition is not so high to inhibit deposition of the aqueous on the precursor mat, or so low so that the composition is too runny to adequately coat the precursor mat.

[0235] The aqueous composition may comprise water in a range of about 75 wt% to about 95 wt% total weight of the aqueous composition. The aqueous composition may comprise water in a range of about 80 wt% to about 90 wt% total weight of the aqueous composition.

[0236] The aqueous composition may comprise a filler as described above.

[0237] The aqueous composition may further comprise at least one additive (e.g. 1 , 2, 3, 4, 5, or more) selected from the group consisting of a biocide, defoamer, pigment, preservative, emulsion stabilizer, wetting and levelling agent, cross-linker, and combinations thereof as described above.

[0238] The aqueous composition may consist essentially of:

[0239] • a binder, which is a polyvinyl alcohol binder with a weight average molecular weight in the range of about 100000 g / mole to about 500000 g / mol;

[0240] • a filler,

[0241] • optionally a defoamer,

[0242] • optionally a viscosity modifier; and

[0243] • water.

[0244] The aqueous composition may consist of:

[0245] • a binder, which is a polyvinyl alcohol binder with a weight average molecular weight in the range of about 100000 g / mole to about 500000 g / mol;

[0246] • a filler,

[0247] • optionally a defoamer,

[0248] • optionally a viscosity modifier; and

[0249] • water. In another aspect, the present invention provides a method for manufacturing the coated non-woven fibrous mat of the present invention, the method comprising the steps of:

[0250] (v) providing a precursor mat comprising glass fibers and a first binder;

[0251] (vi) coating one major surface of the precursor mat with an aqueous composition with a wire bar coating technique, wherein the aqueous composition comprises a second binder, wherein the second binder is a polyvinyl alcohol binder with a weight average molecular weight in the range of about 100000 g / mole to about 500000 g / mol; and

[0252] (vii) drying the coated precursor mat to form the coated non-woven fibrous mat, wherein the coated non-woven fibrous mat has an air permeability of < about 70 L / m2 / s as measured according to ASTM D737.

[0253] The precursor mat, glass fibers, polyester fibers (if any), first binder, second binder, aqueous composition, polyvinyl alcohol binder, weight average molecular weight of the polyvinyl alcohol binder, filler (if any), coated precursor mat, coated non-woven fibrous mat, and air permeability are as described herein.

[0254] One major surface of the precursor mat is coated with the aqueous composition using wire bar coating. A wire bar coating technique is known to the skilled person. A wire bar is a cylindrical bar which has a wire tightly wound around the circumference of the bar for the majority of its length. The wire bar is positioned at a predetermined distance above the precursor mat, or may be in contact with the precursor mat. The aqueous composition is placed on the precursor mat in front of the wire bar in the direction of travel. The wire bar is then moved at a predetermined speed over the precursor mat. The aqueous composition is spread over one major surface of the precursor mat as the wire bar passes over the precursor mat to produce a uniform coating of the aqueous composition on the precursor mat.

[0255] Reverse roll coating is an industrial process which may not be easy to carry out on a smaller or laboratory scale. A wire bar coating technique therefore may conveniently be used in a laboratory to simulate reverse roll coating. The Examples below use an RK multicoater model no K303 Electric Drive as a wire bar coater.

[0256] A wire bar coating technique is not an impregnation or classical size press method. The aqueous composition as described herein is not impregnated through the precursor mat in the wire bar coating method.

[0257] In another aspect, the present invention provides a method for manufacturing the coated non-woven fibrous mat of the present invention, the method comprising the steps of:

[0258] (v) providing a precursor mat comprising glass fibers and a first binder; (vi) coating one major surface of the precursor mat with an aqueous composition with a kiss roll coating technique, wherein the aqueous composition comprises a second binder, wherein the second binder is a polyvinyl alcohol binder with a weight average molecular weight in the range of about 100000 g / mole to about 500000 g / mol; and

[0259] (vii) drying the coated precursor mat to form the coated non-woven fibrous mat, wherein the coated non-woven fibrous mat has an air permeability of < about 70 L / m2 / s as measured according to ASTM D737.

[0260] The precursor mat, glass fibers, polyester fibers (if any), first binder, second binder, aqueous composition, polyvinyl alcohol binder, weight average molecular weight of the polyvinyl alcohol binder, filler (if any), coated precursor mat, coated non-woven fibrous mat, and air permeability are as described herein.

[0261] One major surface of the precursor mat is coated with the aqueous composition using kiss roll coating. A kiss roll coating technique is known to the skilled person. In this respect, a coating roller is typically positioned above a bath of aqueous composition and is partly submerged therein. As the coating roller rotates, the aqueous composition adheres to the coating roller and is transferred onto one major surface of the precursor mat as it passes over the coating roller.

[0262] In an alternative arrangement, the kiss roll coating technique may comprise two coating rollers. One coating roller is positioned substantially above another coating roller. Typically, the coating rollers rotate in the opposite direction to each other. The lower coating roller is typically partly submerged in a bath of aqueous composition such that as it rotates, the aqueous composition adheres to it and is transferred firstly onto the upper coating roller and then onto one major surface of the precursor mat as the precursor mat passes over the upper coating roller.

[0263] Irrespective of the number of coating rollers utilised in the kiss roll coating technique, the quantity of aqueous composition which is coated onto the precursor mat may be influenced by the extent to which the precursor mat is in contact with the coating roller i.e. the extent to which the precursor mat “kisses” the coating roller. A greater quantity of aqueous composition will be coated onto the precursor mat when the precursor mat is in contact with the coating roller or when there is a smaller predetermined gap between the precursor mat and the coating roller. Conversely, the greater the predetermined gap between the precursor mat and the coating roller, the smallerthe quantity of aqueous composition which will be coated onto the precursor mat.

[0264] The coating roller is set up such that it can rotate in the same direction of travel as the precursor mat as the precursor mat passes over the coating roller. Alternatively, the coating roller may rotate in the opposite direction of travel to the precursor mat as the precursor mat passes over the coating roller. In the first instance, a greater quantity of aqueous composition is typically coated onto the precursor mat than the second instance.

[0265] A kiss roll coating technique is not an impregnation or classical size press method. The aqueous composition as described herein is not impregnated through the precursor mat in the wire bar coating method.

[0266] In another aspect, the present invention provides a method for manufacturing the coated non-woven fibrous mat of the present invention, the method comprising the steps of:

[0267] (v) providing a precursor mat comprising glass fibers and a first binder;

[0268] (vi) coating one major surface of the precursor mat with an aqueous composition with a knife coating technique, wherein the aqueous composition comprises a second binder, wherein the second binder is a polyvinyl alcohol binder with a weight average molecular weight in the range of about 100000 g / mole to about 500000 g / mol; and

[0269] (vii) drying the coated precursor mat to form the coated non-woven fibrous mat, wherein the coated non-woven fibrous mat has an air permeability of < about 70 L / m2 / s as measured according to ASTM D737.

[0270] The precursor mat, glass fibers, polyester fibers (if any), first binder, second binder, aqueous composition, polyvinyl alcohol binder, weight average molecular weight of the polyvinyl alcohol binder, coated precursor mat, filler (if any), coated non-woven fibrous mat, and air permeability are as described herein.

[0271] One major surface of the precursor mat is coated with the aqueous composition using a knife coating technique. The knife coating technique may be a knife-over-roll technique. Alternatively, the knife coating technique may be a knife-over-air technique. The knife-over-roll and knife-over-air techniques are known to the skilled person.

[0272] In the knife-over-roll coating technique, a knife is positioned above a roller and the precursor mat passes between them. The roller rotates in the direction of travel of the precursor mat.

[0273] In the knife-over-air coating technique, the precursor mat passes over two rollers, which rotate in the direction of travel of the precursor mat. The knife in this instance is positioned above the precursor mat between the rollers i.e. there is no roller beneath the mat at the point of coating.

[0274] For both the knife-over-roll and knife-over-air techniques, the aqueous composition is deposited onto precursor mat, and is coated onto the precursor mat as it passes between a predetermined gap between the knife blade and precursor mat. Typically, the quantity of aqueous composition which is coated onto the precursor mat is influenced by the width of the predetermined gap. In this respect, the greater the width, the greater the quantity of aqueous composition coated.

[0275] A knife coating technique (such as knife-over-roll or knife-over-air) is not an impregnation or classical size press method. The aqueous composition as described herein is not impregnated through the precursor mat in the wire bar coating method.

[0276] Regardless of the method used to coat the precursor mat, the precursor mat itself may be prepared in a method comprising the steps of:

[0277] (i) providing an aqueous mixture comprising glass fibers and a first binder;

[0278] (ii) forming a dispersion of the aqueous mixture;

[0279] (iii) depositing the aqueous dispersion to form a wetlaid web comprising the glass fibers and the first binder;

[0280] (iv) drying the wetlaid web comprising the glass fibers and the first binder to form the precursor mat.

[0281] The steps for forming the precursor mat may also be referred to as a “co-casting” method. This is because an aqueous mixture comprising the glass fibers is formed together with the first binder.

[0282] Alternatively, the precursor mat may be prepared in a method comprising the steps of:

[0283] (i) providing an aqueous mixture comprising glass fibers;

[0284] (ii) depositing the aqueous mixture to form a wetlaid web comprising the glass fibers;

[0285] (iii) applying an aqueous solution or dispersion of a first binder to the wetlaid web comprising the glass fibers to form a wetlaid web comprising the glass fibers and the first binder;

[0286] (iv) drying the wetlaid web comprising the glass fibers and the first binder to form the precursor mat.

[0287] The first binder may be applied to the web comprising glass fibers by a suitable binder applicator, such as a spray applicator or a curtain coater.

[0288] The flexible precursor mat may be formed by a wet-laid process. The wet-laid process may involve forming an aqueous dispersion, slurry, or mixture of discrete fibers in a mix tank filled with various optional components (sometimes referred to as white water). The aqueous mixture therefore comprises the glass fibers, polyester fibers (if any), the first binder (or combination thereof) and water, and optionally other components such as surfactants, viscosity modifiers, defoaming agents, lubricants, biocides, and / or other chemical agents.

[0289] The dispersion of the aqueous mixture may be obtained by any suitable means provided a uniform or substantially uniform distribution of the glass fibers and optional polyester fibers in the aqueous medium is produced. A uniform distribution of the glass fibers and optional polyester fibers may be produced. Alternatively, a substantially uniform distribution of the glass fibers and optional polyester fibers may be produced. The dispersion may be obtained by a high shear mixing apparatus, such as a rotor / stator mixer.

[0290] The first binder (or combination thereof) may optionally contain conventional additives as described above for the improvement of process and product performance such as dyes, oils, biocides, fillers, colorants, UV stabilizers, coupling agents (e.g., aminosilanes), lubricants, wetting agents, surfactants, and / or antistatic agents.

[0291] The first binder (or combination thereof) may be added at any suitable point in the preparation of the aqueous mixture. For example, the binder (or combination thereof) may be added before, after, or at the same time as the glass fibers and polyester fibers (if any).

[0292] The first binder may be a liquid or solid. When the first binder is a powder, the powdered binder may facilitate co-casting with the fibers in the aqueous solution.

[0293] The aqueous fiber dispersion or slurry may then be processed into a wet-laid mat according to any number of conventional methods known in the art. For example, the aqueous fiber dispersion or slurry is deposited onto a moving screen or conveyor, on which the majority of the water drains through, leaving a randomly oriented fiber web. The water may be removed from the web by a conventional vacuum or air suction system.

[0294] Once the binder has been applied to the wetlaid web of fibers, and first binder, the wetlaid web is passed through at least one drying oven to remove remaining water and cure the binder composition. The fiber web may be further dried by a vacuum slot or other drying means to provide a fiber web.

[0295] The formed precursor mat that emerges from the oven is an assembly of randomly oriented, dispersed, individual fibers. The fiber mat may be rolled onto a take-up roll for storage or later use.

[0296] The precursor mat is substantially or completely coated with the aqueous composition as defined above.

[0297] The aqueous composition of the present invention is prepared by any suitable method, such as mixing the polyvinyl alcohol binder, optional additives (if any), and water.

[0298] The coated non-woven fibrous mat is asymmetric. By “asymmetric”, we mean that the aqueous composition of the present invention does not completely impregnate the precursor mat. Instead, the aqueous composition coats or sits solely on one side of the precursor mat. In this respect, the aqueous composition will be detectable on coated side of the precursor mat but will not be detectable on the other (uncoated) side of the mat. The coated precursor mat is then dried to form the coated non-woven fibrous mat. Typically the coated precursor mat may be passed through at least one drying oven to remove any remaining water and to cure the binder. The mat may be further dried by a vacuum slot or other drying means to provide the coated non-woven fibrous mat as described above.

[0299] Irrespective of the method by which the coated precursor mat is dried, the drying conditions are maintained below the point at which any component of the coated precursor mat degrades (e.g. the first binder, second binder, filler, and / or optional additives (if any)). Therefore, when it is known that one or more components of the coated precursor mat degrades at a particular temperature or vacuum, the drying conditions should be maintained below the degradation temperature or vacuum. Likewise, when it is known that one or more components of the coated precursor mat degrades after drying for a particular period of time, the drying conditions should be maintained for a shorter period of time than the degradation time. With respect to PVOH, care should be taken not to over-dry the coated mats as the PVOH may lose its properties and turn yellow.

[0300] Use of the Coated Non-Woven Fibrous Mat

[0301] When precursor mats are produced using wet-laid procedures and the aqueous fiber dispersion or slurry is deposited onto a moving screen or conveyor, the resulting non-woven fibrous precursor mats typically have a smooth surface (the surface in contact with the moving screen or conveyor, and which may be referred to as the “wire side”) and a non-smooth surface (the surface not in contact with the moving screen or conveyor, and which may be referred to as the “top side”).

[0302] Either the smooth surface or the rough surface may be coated with the aqueous composition as described herein to form the coated non-woven fibrous mat of the invention. Typically, however, the rough surface is the presentation surface. For example, when the coated non-woven fibrous mat is attached to a construction board, the rough surface is faces into the room and the smooth surface attaches to the board.

[0303] In another aspect, the present invention provides a construction board comprising: a first surface and a second surface opposite the first surface, a coated non-woven fibrous mat adhered to the first surface, the second surface or both the first and second surfaces, wherein the coated non-woven fibrous mat is as described herein.

[0304] The construction board may be a polyisocyanurate foam board.

[0305] The coated non-woven fibrous mat is as described herein.

[0306] The coated non-woven fibrous mat may be a facer in the construction board i.e. the facer is adhered to a first surface, a second surface or both first and second surfaces to form a construction board. The construction board may further comprise a layer of ink as the outermost layer of the first surface, the second surface or both the first and second surfaces of the construction board.

[0307] Embodiments and / or optional features of the invention have been described above. Any aspect of the invention may be combined with any other aspect of the invention, unless the context demands otherwise. Any of the embodiments or optional features of any aspect may be combined, singly or in combination, with any aspect of the invention, unless the context demands otherwise.

[0308] The invention will now be described further by reference to the following examples, which are intended to illustrate but not limit, the scope of the invention.

[0309] Examples

[0310] Example 1

[0311] Four commercially available polyvinylalcohols (PVOHs) are obtained from Kuraray in powder form. The PVOHs are Mowiol® or Poval™ 4-98, 5-74, 28-99, 56-98, and 95-88.

[0312] 200g of each powder is dissolved in 1 .8 L of demineralised water under stirring at 600 rpm for 4 hours at 85 °C with a VMI agitator. The solutions are diluted with further demineralised water to adjust the solid content as appropriate.

[0313] A4 sized sheets of glass non-woven precursor are coated with each solution of PVOH using a wire bar coating method. In this respect, a laboratory RK multicoater model NO K303 Electric Drive is utilised. The multicoater is fitted with a meter bar (meter bar 0) and each coating is applied at a coating speed of 10 meters per minute.

[0314] The precursor mat has a basis weight of 65g / m2and an air permeability of 1900L / m2 / s before being coated.

[0315] The glass fibers in the precursor mat have a mean fiber diameter of about 10 pm, and a mean fiber length of about 6 mm.

[0316] Mowiol® 4-98, Poval™ 5-74, and Poval™ 95-88 are each applied to the precursor mat at a concentration of 10 wt%. Mowiol® 28-99 is applied to the precursor mat at a concentration of 8 wt%. Poval™ 56-98 is applied to the precursor mat at a concentration of 11 wt%.

[0317] §measured at room temperature (about 20°C) with a Brookfield synchronized-motor rotary viscometer at a Torque comprised between 40 to 70%.

[0318] * not according to the invention

[0319] * according to the invention

[0320] After coating, the coated non-woven fibrous mats are dried in an oven. The oven temperature is aboutl 70°C and the total drying time about 60 seconds. Care is taken not to over-dry the coated mats as the PVOH may lose its properties and turn yellow.

[0321] After drying, the coated non-woven fibrous mats are cut in to 10 x 10 cm samples. The air permeabilities of the coated mats are determined using an air permeability tester FX3300 (TEXTEST Instruments). The air permeability is determined according to ASTM D737. The air flow is set at a pressure of 100 Pa.

[0322] The table below details the measured air permeabilities for the coated non-woven fibrous mats:

[0323] * not according to the invention

[0324] * according to the invention

[0325] Aqueous coating composition comprising Mowiol® 4-98 and Poval™ 5-74 are not according to the invention. These PVOHs are not sufficiently viscous to close the precursor non-woven fibrous mat. When precursor mats are coated with aqueous compositions comprising these PVOHs, the coated non- woven fibrous mats have high air permeabilities. Mats coated with these PVOHs therefore are not suitable for use in the preparation of polyisocyanurate insulation boards.

[0326] Aqueous coating compositions comprising Mowiol® 28-99, Poval™56-98, and 95-88 are according to the invention. These PVOHs are suitably viscous to close the precursor non-woven fibrous mat. When precursor mats are coated with aqueous compositions comprising these PVOHs, the dried coated nonwoven fibrous mats have low to very low air permeabilities i.e. the mats are very impermeable. Mats coated with these PVOHs therefore are suitable for use in the preparation of polyisocyanurate insulation boards.

[0327] Figure 1 shows a representative photograph of a coated non-woven fibrous mat coated with a 10 wt% solution of Mowiol® 28-99 using the RK laboratory multicoater. Figure 1 illustrates that the coating composition substantially fills the gaps between the glass fibers of the non-woven fibrous mat, and therefore reduces the air permeability of the coated non-woven fibrous mat.

[0328] Example 2 (according to the invention)

[0329] Mowiol® 28-99 is dissolved in tap water to obtain a 10 wt% solution (coating 1).

[0330] An Mg(OH)2 slurry (53% in water) and Mowiol® 28-99 (10% in water) are mixed to prepare two coatings (Coatings 2 and 3).

[0331] Aluminium trihydrate (ATH) and Mowiol® 28-99 (10% in water) are mixed to prepare Coating 4.

[0332] Wet % wt in coatings 2 to 4:

[0333] Coatings 1-4 are individually applied to sheets of glass non-woven precursor using a wire bar coating method. A laboratory RK multicoater model NO K303 Electric Drive is utilised. The multicoater is fitted with a meter bar (meter bar 0) and each coating is applied at a coating speed of 10 meters per minute. The target add-on for each sample is 25-35 g / m2.

[0334] This precursor mat has a basis weight of 65g / m2and an air permeability of 1900L / m2 / s before being coated. The glass fibers in the precursor mat have a mean fiber diameter of about 10 pm, and a mean fiber length of about 6 mm.

[0335] After coating, the coated non-woven fibrous mats are dried in an oven. The oven temperature is about 170°C and the total drying time about 60 seconds. Care is taken not to over-dry the coated mats as the PVOH may lose its properties and turn yellow.

[0336] Four samples of each coating are prepared (20 cm x 20 cm).

[0337] Dry % solids in coatings 1 and 2:

[0338] After drying, the coated non-woven fibrous mats are cut in to 10 x 10 cm samples. The air permeabilities of the coated mats are determined using an air permeability tester FX3300 (TEXTEST Instruments). The air permeability is determined according to ASTM D737. The air flow is set at a pressure of 100 Pa.

[0339] The table below details the average measured air permeabilities for the coated non-woven fibrous mats:

[0340] Dried coated non-woven fibrous mats 1-4 have low to very low air permeabilities i.e. the mats are very impermeable. The coated mats 1-4 therefore are suitable for use in the preparation of polyisocyanurate insulation boards.

[0341] In addition, coated mats 2-4 demonstrate that magnesium hydroxide and aluminium trihydrate can be incorporated into the coating of the coated non-woven fibrous mats as fire retardants. Coated Mats 2- 4 retain their suitability for use in the preparation of polyisocyanurate insulation boards as they have average air permeabilities <70 L / m2 / s.

Claims

Claims1 . A coated non-woven fibrous mat, the coated non-woven fibrous mat comprising:(a) a precursor mat comprising:• a non-woven web of fibers comprising glass fibers, and• a first binder; and(b) a coating which coats the precursor mat, wherein the coating comprises a second binder, wherein the second binder is a polyvinyl alcohol binder with a weight average molecular weight in the range of about 100000 g / mole to about 500000 g / mol; wherein: the coated non-woven fibrous mat has an air permeability of < about 70 L / m2 / s as measured according to ASTM D737.

2. A coated non-woven fibrous mat according to claim 1 , wherein the polyvinyl alcohol has a viscosity measured at 4 wt% of said polyvinyl alcohol in water at room temperature with a Brookfield synchronized-motor rotary viscometer of > about 25 mPa.s and < about 98 mPa.s, optionally > about 25 mPa.s and < about 60 mPa.s.

3. A coated non-woven fibrous mat according to claim 1 or claim 2, wherein the first binder comprises a polyvinyl alcohol binder, optionally a polyvinyl alcohol binder with a weight average molecular weight in the range of about 100000 g / mole to about 500000 g / mol.

4. A coated non-woven fibrous mat according to any one of the preceding claims, wherein the coating: a) further comprises a filler, optionally aluminum trihydrate and / or magnesium hydroxide and / or calcium carbonate; and / or b) penetrates the precursor mat between > about 0.5% to < about 50% of the thickness of the precursor mat as measured in accordance with ASTM D1777, optionally between > about 5% to < about 30% of the thickness of the precursor mat as measured in accordance with ASTM D1777; and / or c) has a weight in the range of about 10 to about 50 gsm; and / or d) does not comprise added poly- or per-fluoroalkyl substances.

5. A coated non-woven fibrous mat according to any one of the preceding claims, wherein the second binder is: a) a polyvinyl alcohol having a degree of hydrolysis > about 85 mol%, optionally > about 95 mol% and < about 99.9 mol%, optionally > about 95 mol% and < about 98 mol%; and / orb) a polyvinyl alcohol with a weight average molecular weight in the range of 140000 to 250000 g / mol.

6. A coated non-woven fibrous mat according to any one of the preceding claims, wherein the coated non-woven fibrous mat has an air permeability in the range of about 1 L / m2 / s to about 70 L / m2 / s measured in accordance with ASTM D737, optionally in the range of about 5 L / m2 / s to about 65 L / m2 / s measured in accordance with ASTM D737, optionally in the range of about 5 to about 20 L / m2 / s.

7. A method for manufacturing a coated non-woven fibrous mat comprising the steps of:(v) providing a precursor mat comprising glass fibers and a first binder;(vi) coating one major surface of the precursor mat with an aqueous composition with a reverse roll technique, a wire bar coating technique, a kiss roll coating technique, or a knife coating technique, wherein the aqueous composition comprises a second binder, wherein the second binder is a polyvinyl alcohol binder with a weight average molecular weight in the range of about 100000 g / mole to about 500000 g / mol; and(vii) drying the coated precursor mat to form a coated non-woven fibrous mat, wherein the coated non-woven fibrous mat has an air permeability of < about 70 L / m2 / s as measured according to ASTM D737.

8. A method according to claim 7, wherein the coating technique is a reverse roll technique.

9. A method according to claim 7, wherein the knife coating technique is a knife-over-roll technique or knife-over-air technique.

10. A method according to any one of claims 7 to 9, wherein the polyvinyl alcohol has a viscosity measured at 4 wt% of said polyvinyl alcohol in water at room temperature with a Brookfield synchronized-motor rotary viscometer of > about 25 mPa.s and < about 98 mPa.s, optionally > about 25 mPa.s and < about 60 mPa.s.11 . A method according to any one of claims 7 to 10, wherein the first binder comprises a polyvinyl alcohol binder, optionally a polyvinyl alcohol binder with a weight average molecular weight in the range of about 100000 g / mole to about 500000 g / mol.

12. A method according to any one of claims 7 to 11 , wherein the aqueous composition has a viscosity in the range from > about 500 mPa.s to < about 5000 mPa.s as measured at room temperature using a Brookfield synchronized-motor rotary viscometer, optionally in the range from > about 1000 mPa.s and < about 5000 mPa.s as measured at room temperature using a Brookfield synchronized-motor rotary viscometer.

13. A method according to any one of claims 7 to 12, wherein the second binder is: a) a polyvinyl alcohol having a degree of hydrolysis > about 85 mol%, optionally > about 95 mol% and < about 99.9 mol%, optionally > about 95 mol% and < about 98 mol%; and / or b) a polyvinyl alcohol with a weight average molecular weight in the range of 140000 to 250000 g / mol; and / or c) a polyvinyl alcohol present in a range of about 5 wt% to about 15 wt% ofthe total weight of the aqueous composition, optionally in the range of about 8 wt% to about 11 wt% of the total weight of the aqueous composition.

14. A method according to any one of claims 7 to 13, wherein the precursor mat is prepared in a method comprising the steps of:(i) providing an aqueous mixture comprising glass fibers and a first binder;(ii) forming a dispersion of the aqueous mixture;(iii) depositing the aqueous dispersion to form a wetlaid web comprising the glass fibers and the first binder;(iv) drying the wetlaid web comprising the glass fibers and the first binder to form the precursor mat.

15. A method according to any one of claims 7 to 13, wherein the precursor mat is prepared in a method comprising the steps of:(i) providing an aqueous mixture comprising glass fibers;(ii) depositing the aqueous mixture to form a wetlaid web comprising glass fibers;(iii) applying an aqueous solution or dispersion of a first binder to the wetlaid web comprising the glass fibers to form a wetlaid web comprising the glass fibers and the first binder;(iv) drying the wetlaid web comprising the glass fibers and the first binder to form the precursor mat.

16. A construction board comprising: a first surface and a second surface opposite the first surface, a coated non-woven fibrous mat adhered to the first surface, the second surface or both the first and second surfaces, wherein the coated non-woven fibrous mat is according to any one of claims 1 to 6.

17. A construction board according to claim 16, wherein the construction board is a polyisocyanurate foam board.

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