3.1 Phillip Lim will not rush its expansion into the mainland

Phillip Lim is taking us on a tour of his brand's new store in New York - a huge but minimalist space, with high ceilings and quirky furnishings he hand-picked - when his business partner, Wen Zhou, walks in.

Both ooze style: Lim in a raw-edged black shirt and black pants rolled up at the bottom, white socks peeking from rubber-soled white skater slip-ons; and Zhou in a sleek, tailored denim suit, crisp white shirt and shiny gold-chain loafers.

The launch of the 3.1 Phillip Lim store during New York Fashion Week is a coup for the pair. "I spend a lot of time on these streets," says Lim, who heads the brand's creative side, which includes everything from collections to retail interiors.

"A lot of my favourite restaurants are here, and so is my favourite furniture store. I used to visit, and now I live here, and I find that funny," he says.

The new boutique is on Great Jones Street near the Bowery, an area that's going through a period of gentrification.

"The canvases on the walls make it feel like my apartment. I live in a loft in SoHo, and I'm always changing things around. So I wanted something open, inspired by art," says Lim.

Fun is the aim: sunglasses are placed on a bed of green mink, which looks like a putting green. "Even the accessories get to relax here," Lim says, laughing.

Lim selected all the furniture, including the 1940s chairs and the marble plinths. His additions give the 4,000 sq ft space an intimate feel.

Intimacy is also the idea behind Lim's new spring-summer 2015 collection, which debuted just days before our meeting at the store.

It's inspired by the "intimacy of bedroom interiors" and features flashes of skin peeking from asymmetrical tied tops reminiscent of bedroom robes.

Sensual curved lines snake around the body on tops, skirts and bolero jackets, opulent brocade is paired with easy tailoring, and the easy-going aesthetic that US designers do so well.

"I looked at alternate routes. I wanted to explore the routes of intimacy and doing it your own way," Lim says.

Across the road at a cafe, Zhou - who heads the brand's business side - gives more clues about what kind of company they aim to be. There's no doubt that the brand, along with Alexander Wang and Altuzarra, is at the forefront of the powerful American-Asian wave in fashion. The brand is increasing in global appeal, especially in Asia, and is starting to enjoy a covetable position in the luxury market.

Mother-of-two Zhou was born in a village in Ningbo, China, and migrated to New York with her family in 1985 when she was 12.

"I started out on a typical journey of being a first-generation Chinese immigrant," she says. "I went to school not knowing the language and grew up in a sketchy neighbourhood in New York.

"The Lower East Side was not like it is today; it was not very pretty. That taught me how to survive and I eventually went to school at the Fashion Institute of Technology."

She had several jobs before she started in fashion, even doing stints in a sweatshop and McDonald's. She finally started her own fabric company, of which Lim became a client. "I noticed he was choosing all these crazy fabrics that I loved, before I even met him. I remember wondering who he was. One thing led to another and we eventually met in Paris and became friends. Phillip is supportive and very much into the craft of fashion."

They co-founded the brand in 2005 and now have hundreds of points of sale globally. There are stand-alone stores in Hong Kong, Los Angeles, Tokyo, Beijing, Shanghai and Singapore.

"We are looking at Malaysia, Thailand, and Southeast Asia," says Lim about plans for further store openings, "but expansion will be slow and organic."

While other brands rush to flood the Chinese market, Zhou says that speed is not part of their plan. "Our retail strategy is honest, sincere and relevant. It's slow and steady," she says.

"We are Chinese and that is part of our DNA. Our roots are in China," Zhou says. "Because of that, I'm more protective of that region. There is huge growth potential there, but I'm trying to slow down a bit because I want to do it right."

"Eventually, China will be our biggest market, but we've seen the dangers of overexposure. There is no need to saturate the market. Design and beauty have to be celebrated."

As pioneers of a very specific type of modern luxury, Zhou and Lim say that, nine years later, there are a lot more brands in this market segment, so it's all about "trying to stay relevant and ahead of the times".

"What makes us different from other partnerships," Zhou says, "is that Phillip has a very clear business sense and, although I handle the business, I am very sensitive to design. We are a design-led company, we are not a margin-driven, bottom-line-driven company. We look at the creative side first."

Zhou says she still runs the business like a start-up. It's a "culture, rather than a machine", she says. Despite the brand's rapid rise, they only added a human resources department a year ago.

"We have 125 employees and I make sure that I know everyone's name," says Zhou. "I want them to know who they work for and what our mission is."